diff --git a/.github/workflows/daily-tests.yml b/.github/workflows/daily-tests.yml
index b53c19cf..423dc2d2 100644
--- a/.github/workflows/daily-tests.yml
+++ b/.github/workflows/daily-tests.yml
@@ -87,6 +87,12 @@ jobs:
       - name: Check unbuffered client 
         run: cargo run --locked --bin unbuffered-client
 
+      - name: Check unbuffered tokio client 
+        run: cargo run --locked --bin unbuffered-async-client
+
+      - name: Check unbuffered async-std client 
+        run: cargo run --locked --bin unbuffered-async-client --features=async-std
+
       # Test the server_acceptor binary builds - we invoke with --help since it
       # will run a server process that doesn't exit when invoked with no args
       - name: Check server acceptor
diff --git a/Cargo.lock b/Cargo.lock
index bc9cb330..a5bba3cb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -115,6 +115,161 @@ version = "1.0.75"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a4668cab20f66d8d020e1fbc0ebe47217433c1b6c8f2040faf858554e394ace6"
 
+[[package]]
+name = "async-attributes"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a3203e79f4dd9bdda415ed03cf14dae5a2bf775c683a00f94e9cd1faf0f596e5"
+dependencies = [
+ "quote",
+ "syn 1.0.109",
+]
+
+[[package]]
+name = "async-channel"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81953c529336010edd6d8e358f886d9581267795c61b19475b71314bffa46d35"
+dependencies = [
+ "concurrent-queue",
+ "event-listener 2.5.3",
+ "futures-core",
+]
+
+[[package]]
+name = "async-channel"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ca33f4bc4ed1babef42cad36cc1f51fa88be00420404e5b1e80ab1b18f7678c"
+dependencies = [
+ "concurrent-queue",
+ "event-listener 4.0.0",
+ "event-listener-strategy",
+ "futures-core",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "async-executor"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17ae5ebefcc48e7452b4987947920dac9450be1110cadf34d1b8c116bdbaf97c"
+dependencies = [
+ "async-lock 3.2.0",
+ "async-task",
+ "concurrent-queue",
+ "fastrand 2.0.1",
+ "futures-lite 2.1.0",
+ "slab",
+]
+
+[[package]]
+name = "async-global-executor"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b4353121d5644cdf2beb5726ab752e79a8db1ebb52031770ec47db31d245526"
+dependencies = [
+ "async-channel 2.1.1",
+ "async-executor",
+ "async-io 2.2.1",
+ "async-lock 3.2.0",
+ "blocking",
+ "futures-lite 2.1.0",
+ "once_cell",
+]
+
+[[package]]
+name = "async-io"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fc5b45d93ef0529756f812ca52e44c221b35341892d3dcc34132ac02f3dd2af"
+dependencies = [
+ "async-lock 2.8.0",
+ "autocfg",
+ "cfg-if",
+ "concurrent-queue",
+ "futures-lite 1.13.0",
+ "log",
+ "parking",
+ "polling 2.8.0",
+ "rustix 0.37.27",
+ "slab",
+ "socket2 0.4.10",
+ "waker-fn",
+]
+
+[[package]]
+name = "async-io"
+version = "2.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6d3b15875ba253d1110c740755e246537483f152fa334f91abd7fe84c88b3ff"
+dependencies = [
+ "async-lock 3.2.0",
+ "cfg-if",
+ "concurrent-queue",
+ "futures-io",
+ "futures-lite 2.1.0",
+ "parking",
+ "polling 3.3.1",
+ "rustix 0.38.28",
+ "slab",
+ "tracing",
+ "windows-sys 0.52.0",
+]
+
+[[package]]
+name = "async-lock"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "287272293e9d8c41773cec55e365490fe034813a2f172f502d6ddcf75b2f582b"
+dependencies = [
+ "event-listener 2.5.3",
+]
+
+[[package]]
+name = "async-lock"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7125e42787d53db9dd54261812ef17e937c95a51e4d291373b670342fa44310c"
+dependencies = [
+ "event-listener 4.0.0",
+ "event-listener-strategy",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "async-std"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62565bb4402e926b29953c785397c6dc0391b7b446e45008b0049eb43cec6f5d"
+dependencies = [
+ "async-attributes",
+ "async-channel 1.9.0",
+ "async-global-executor",
+ "async-io 1.13.0",
+ "async-lock 2.8.0",
+ "crossbeam-utils",
+ "futures-channel",
+ "futures-core",
+ "futures-io",
+ "futures-lite 1.13.0",
+ "gloo-timers",
+ "kv-log-macro",
+ "log",
+ "memchr",
+ "once_cell",
+ "pin-project-lite",
+ "pin-utils",
+ "slab",
+ "wasm-bindgen-futures",
+]
+
+[[package]]
+name = "async-task"
+version = "4.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4eb2cdb97421e01129ccb49169d8279ed21e829929144f4a22a6e54ac549ca1"
+
 [[package]]
 name = "async-trait"
 version = "0.1.74"
@@ -123,9 +278,15 @@ checksum = "a66537f1bb974b254c98ed142ff995236e81b9d0fe4db0575f46612cb15eb0f9"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.40",
 ]
 
+[[package]]
+name = "atomic-waker"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -216,7 +377,7 @@ dependencies = [
  "regex",
  "rustc-hash",
  "shlex",
- "syn",
+ "syn 2.0.40",
  "which",
 ]
 
@@ -241,6 +402,28 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "blocking"
+version = "1.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a37913e8dc4ddcc604f0c6d3bf2887c995153af3611de9e23c352b44c1b9118"
+dependencies = [
+ "async-channel 2.1.1",
+ "async-lock 3.2.0",
+ "async-task",
+ "fastrand 2.0.1",
+ "futures-io",
+ "futures-lite 2.1.0",
+ "piper",
+ "tracing",
+]
+
+[[package]]
+name = "bumpalo"
+version = "3.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f30e7476521f6f8af1a1c4c0b8cc94f0bee37d91763d0ca2665f299b6cd8aec"
+
 [[package]]
 name = "byteorder"
 version = "1.5.0"
@@ -354,7 +537,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.40",
 ]
 
 [[package]]
@@ -378,6 +561,15 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
 
+[[package]]
+name = "concurrent-queue"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d16048cd947b08fa32c24458a22f5dc5e835264f689f4f5653210c69fd107363"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "const-oid"
 version = "0.9.5"
@@ -481,7 +673,7 @@ checksum = "f46882e17999c6cc590af592290432be3bce0428cb0d5f8b6715e4dc7b383eb3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.40",
 ]
 
 [[package]]
@@ -588,7 +780,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.40",
 ]
 
 [[package]]
@@ -620,6 +812,48 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "event-listener"
+version = "2.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0206175f82b8d6bf6652ff7d71a1e27fd2e4efde587fd368662814d6ec1d9ce0"
+
+[[package]]
+name = "event-listener"
+version = "4.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "770d968249b5d99410d61f5bf89057f3199a077a04d087092f58e7d10692baae"
+dependencies = [
+ "concurrent-queue",
+ "parking",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "event-listener-strategy"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "958e4d70b6d5e81971bebec42271ec641e7ff4e170a6fa605f2b8a8b65cb97d3"
+dependencies = [
+ "event-listener 4.0.0",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "fastrand"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e51093e27b0797c359783294ca4f0a911c270184cb10f85783b118614a1501be"
+dependencies = [
+ "instant",
+]
+
+[[package]]
+name = "fastrand"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25cbce373ec4653f1a01a31e8a5e5ec0c622dc27ff9c4e6606eefef5cbbed4a5"
+
 [[package]]
 name = "ff"
 version = "0.13.0"
@@ -678,6 +912,34 @@ version = "0.3.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8bf34a163b5c4c52d0478a4d757da8fb65cabef42ba90515efee0f6f9fa45aaa"
 
+[[package]]
+name = "futures-lite"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49a9d51ce47660b1e808d3c990b4709f2f415d928835a17dfd16991515c46bce"
+dependencies = [
+ "fastrand 1.9.0",
+ "futures-core",
+ "futures-io",
+ "memchr",
+ "parking",
+ "pin-project-lite",
+ "waker-fn",
+]
+
+[[package]]
+name = "futures-lite"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aeee267a1883f7ebef3700f262d2d54de95dfaf38189015a74fdc4e0c7ad8143"
+dependencies = [
+ "fastrand 2.0.1",
+ "futures-core",
+ "futures-io",
+ "parking",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "futures-sink"
 version = "0.3.29"
@@ -756,6 +1018,18 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
 
+[[package]]
+name = "gloo-timers"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b995a66bb87bebce9a0f4a95aed01daca4872c050bfcb21653361c03bc35e5c"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "group"
 version = "0.13.0"
@@ -997,13 +1271,33 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "instant"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a5bbe824c507c5da5956355e86a746d82e0e1464f65d862cc5e71da70e94b2c"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "io-lifetimes"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eae7b9aee968036d54dce06cebaefd919e4472e753296daccd6d344e3e2df0c2"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "ipconfig"
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b58db92f96b720de98181bbbe63c831e87005ab460c1bf306eb2622b4707997f"
 dependencies = [
- "socket2",
+ "socket2 0.5.5",
  "widestring",
  "windows-sys 0.48.0",
  "winreg",
@@ -1022,7 +1316,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cb0889898416213fab133e1d33a0e5858a48177452750691bde3666d0fdbaf8b"
 dependencies = [
  "hermit-abi",
- "rustix",
+ "rustix 0.38.28",
  "windows-sys 0.48.0",
 ]
 
@@ -1041,6 +1335,24 @@ version = "1.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b1a46d1a171d865aa5f83f92695765caa047a9b4cbae2cbf37dbd613a793fd4c"
 
+[[package]]
+name = "js-sys"
+version = "0.3.66"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cee9c64da59eae3b50095c18d3e74f8b73c0b86d2792824ff01bbce68ba229ca"
+dependencies = [
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "kv-log-macro"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0de8b303297635ad57c9f5059fd9cee7a47f8e8daa09df0fcd07dd39fb22977f"
+dependencies = [
+ "log",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -1084,6 +1396,12 @@ version = "0.5.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0717cef1bc8b636c6e1c1bbdefc09e6322da8a9321966e8928ef80d20f7f770f"
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef53942eb7bf7ff43a617b3e2c1c4a5ecf5944a7c1bc12d7ee39bbb15e5c1519"
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.4.12"
@@ -1105,6 +1423,9 @@ name = "log"
 version = "0.4.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5e6163cb8c49088c2c36f57875e58ccd8c87c7427f7fbd50ea6710b2f3f2e8f"
+dependencies = [
+ "value-bag",
+]
 
 [[package]]
 name = "lru-cache"
@@ -1280,6 +1601,12 @@ dependencies = [
  "primeorder",
 ]
 
+[[package]]
+name = "parking"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb813b8af86854136c6922af0598d719255ecb2179515e6e7730d468f05c9cae"
+
 [[package]]
 name = "parking_lot"
 version = "0.12.1"
@@ -1343,6 +1670,17 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
+[[package]]
+name = "piper"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "668d31b1c4eba19242f2088b2bf3316b82ca31082a8335764db4e083db7485d4"
+dependencies = [
+ "atomic-waker",
+ "fastrand 2.0.1",
+ "futures-io",
+]
+
 [[package]]
 name = "pkcs1"
 version = "0.7.5"
@@ -1370,6 +1708,36 @@ version = "3.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "14e6ab3f592e6fb464fc9712d8d6e6912de6473954635fd76a589d832cffcbb0"
 
+[[package]]
+name = "polling"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b2d323e8ca7996b3e23126511a523f7e62924d93ecd5ae73b333815b0eb3dce"
+dependencies = [
+ "autocfg",
+ "bitflags 1.3.2",
+ "cfg-if",
+ "concurrent-queue",
+ "libc",
+ "log",
+ "pin-project-lite",
+ "windows-sys 0.48.0",
+]
+
+[[package]]
+name = "polling"
+version = "3.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf63fa624ab313c11656b4cda960bfc46c410187ad493c41f6ba2d8c1e991c9e"
+dependencies = [
+ "cfg-if",
+ "concurrent-queue",
+ "pin-project-lite",
+ "rustix 0.38.28",
+ "tracing",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "poly1305"
 version = "0.8.0"
@@ -1412,7 +1780,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ae005bd773ab59b4725093fd7df83fd7892f7d8eafb48dbd7de6e024e4215f9d"
 dependencies = [
  "proc-macro2",
- "syn",
+ "syn 2.0.40",
 ]
 
 [[package]]
@@ -1624,6 +1992,20 @@ dependencies = [
  "semver",
 ]
 
+[[package]]
+name = "rustix"
+version = "0.37.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fea8ca367a3a01fe35e6943c400addf443c0f57670e6ec51196f71a4b8762dd2"
+dependencies = [
+ "bitflags 1.3.2",
+ "errno",
+ "io-lifetimes",
+ "libc",
+ "linux-raw-sys 0.3.8",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "rustix"
 version = "0.38.28"
@@ -1633,7 +2015,7 @@ dependencies = [
  "bitflags 2.4.1",
  "errno",
  "libc",
- "linux-raw-sys",
+ "linux-raw-sys 0.4.12",
  "windows-sys 0.52.0",
 ]
 
@@ -1698,6 +2080,7 @@ dependencies = [
 name = "rustls-examples"
 version = "0.0.1"
 dependencies = [
+ "async-std",
  "docopt",
  "env_logger",
  "log",
@@ -1708,6 +2091,7 @@ dependencies = [
  "rustls-pki-types",
  "serde",
  "serde_derive",
+ "tokio",
  "webpki-roots 0.26.0",
 ]
 
@@ -1852,7 +2236,7 @@ checksum = "43576ca501357b9b071ac53cdc7da8ef0cbd9493d8df094cd821777ea6e894d3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.40",
 ]
 
 [[package]]
@@ -1908,6 +2292,16 @@ version = "1.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4dccd0940a2dcdf68d092b8cbab7dc0ad8fa938bf95787e1b916b0e3d0e8e970"
 
+[[package]]
+name = "socket2"
+version = "0.4.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f7916fc008ca5542385b89a3d3ce689953c143e9304a9bf8beec1de48994c0d"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "socket2"
 version = "0.5.5"
@@ -1952,6 +2346,17 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "81cdd64d312baedb58e21336b31bc043b77e01cc99033ce76ef539f78e965ebc"
 
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.40"
@@ -1989,7 +2394,7 @@ checksum = "266b2e40bc00e5a6c09c3584011e08b06f123c00362c92b975ba9843aaaa14b8"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.40",
 ]
 
 [[package]]
@@ -2037,10 +2442,22 @@ dependencies = [
  "mio",
  "num_cpus",
  "pin-project-lite",
- "socket2",
+ "socket2 0.5.5",
+ "tokio-macros",
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "tokio-macros"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b8a1e28f2deaa14e508979454cb3a223b10b938b45af148bc0986de36f1923b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.40",
+]
+
 [[package]]
 name = "tokio-rustls"
 version = "0.24.1"
@@ -2084,7 +2501,7 @@ checksum = "34704c8d6ebcbc939824180af020566b01a7c01f80641264eba0999f6c2b6be7"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.40",
 ]
 
 [[package]]
@@ -2162,18 +2579,106 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
 
+[[package]]
+name = "value-bag"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a72e1902dde2bd6441347de2b70b7f5d59bf157c6c62f0c44572607a1d55bbe"
+
 [[package]]
 name = "version_check"
 version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "waker-fn"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3c4517f54858c779bbcbf228f4fca63d121bf85fbecb2dc578cdf4a39395690"
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.89"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ed0d4f68a3015cc185aff4db9506a015f4b96f95303897bfa23f846db54064e"
+dependencies = [
+ "cfg-if",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.89"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b56f625e64f3a1084ded111c4d5f477df9f8c92df113852fa5a374dbda78826"
+dependencies = [
+ "bumpalo",
+ "log",
+ "once_cell",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.40",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-futures"
+version = "0.4.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac36a15a220124ac510204aec1c3e5db8a22ab06fd6706d881dc6149f8ed9a12"
+dependencies = [
+ "cfg-if",
+ "js-sys",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.89"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0162dbf37223cd2afce98f3d0785506dcb8d266223983e4b5b525859e6e182b2"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.89"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0eb82fcb7930ae6219a7ecfd55b217f5f0893484b7a13022ebb2b2bf20b5283"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.40",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.89"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ab9b36309365056cd639da3134bf87fa8f3d86008abf99e612384a6eecd459f"
+
+[[package]]
+name = "web-sys"
+version = "0.3.66"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "50c24a44ec86bb68fbecd1b3efed7e85ea5621b39b35ef2766b66cd984f8010f"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "webpki-roots"
 version = "0.25.3"
@@ -2198,7 +2703,7 @@ dependencies = [
  "either",
  "home",
  "once_cell",
- "rustix",
+ "rustix 0.38.28",
 ]
 
 [[package]]
@@ -2418,5 +2923,5 @@ checksum = "ce36e65b0d2999d2aafac989fb249189a141aee1f53c612c1f37d72631959f69"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.40",
 ]
diff --git a/examples/Cargo.toml b/examples/Cargo.toml
index edfb44ca..e2f90b7b 100644
--- a/examples/Cargo.toml
+++ b/examples/Cargo.toml
@@ -7,6 +7,7 @@ description = "Rustls example code and tests."
 publish = false
 
 [dependencies]
+async-std = { version = "1.12.0", features = ["attributes"], optional = true }
 docopt = "~1.1"
 env_logger = "0.10"
 log = { version = "0.4.4" }
@@ -17,4 +18,5 @@ rustls = { path = "../rustls", features = [ "logging" ]}
 rustls-pemfile = "2"
 serde = "1.0"
 serde_derive = "1.0"
+tokio = { version = "1.34.0", features = ["io-util", "macros", "net", "rt"]}
 webpki-roots = "0.26"
diff --git a/examples/src/bin/unbuffered-async-client.rs b/examples/src/bin/unbuffered-async-client.rs
new file mode 100644
index 00000000..db3ec56d
--- /dev/null
+++ b/examples/src/bin/unbuffered-async-client.rs
@@ -0,0 +1,263 @@
+use std::error::Error;
+use std::sync::Arc;
+
+#[cfg(feature = "async-std")]
+use async_std::io::{ReadExt, WriteExt};
+#[cfg(feature = "async-std")]
+use async_std::net::TcpStream;
+use rustls::client::{ClientConnectionData, UnbufferedClientConnection};
+use rustls::unbuffered::{
+    AppDataRecord, ConnectionState, EncodeError, EncryptError, InsufficientSizeError,
+    UnbufferedStatus, WriteTraffic,
+};
+#[allow(unused_imports)]
+use rustls::version::{TLS12, TLS13};
+use rustls::{ClientConfig, RootCertStore};
+#[cfg(not(feature = "async-std"))]
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+#[cfg(not(feature = "async-std"))]
+use tokio::net::TcpStream;
+
+const SERVER_NAME: &str = "example.com";
+const PORT: u16 = 443;
+
+const KB: usize = 1024;
+const INCOMING_TLS_BUFSIZE: usize = 16 * KB;
+const OUTGOING_TLS_INITIAL_BUFSIZE: usize = KB;
+
+const MAX_ITERATIONS: usize = 20;
+
+#[cfg_attr(not(feature = "async-std"), tokio::main(flavor = "current_thread"))]
+#[cfg_attr(feature = "async-std", async_std::main)]
+async fn main() -> Result<(), Box<dyn Error>> {
+    let root_store = RootCertStore {
+        roots: webpki_roots::TLS_SERVER_ROOTS.into(),
+    };
+
+    let config = ClientConfig::builder_with_protocol_versions(&[&TLS13])
+        .with_root_certificates(root_store)
+        .with_no_client_auth();
+
+    let config = Arc::new(config);
+
+    let mut incoming_tls = [0; INCOMING_TLS_BUFSIZE];
+    let mut outgoing_tls = vec![0; OUTGOING_TLS_INITIAL_BUFSIZE];
+
+    converse(&config, &mut incoming_tls, &mut outgoing_tls).await?;
+
+    Ok(())
+}
+
+async fn converse(
+    config: &Arc<ClientConfig>,
+    incoming_tls: &mut [u8],
+    outgoing_tls: &mut Vec<u8>,
+) -> Result<(), Box<dyn Error>> {
+    let mut conn = UnbufferedClientConnection::new(Arc::clone(config), SERVER_NAME.try_into()?)?;
+    let mut sock = TcpStream::connect(format!("{SERVER_NAME}:{PORT}")).await?;
+
+    let mut incoming_used = 0;
+    let mut outgoing_used = 0;
+
+    let mut open_connection = true;
+    let mut sent_request = false;
+    let mut received_response = false;
+
+    let mut iter_count = 0;
+    while open_connection {
+        let UnbufferedStatus { mut discard, state } =
+            conn.process_tls_records(&mut incoming_tls[..incoming_used])?;
+
+        match dbg!(state) {
+            ConnectionState::ReadTraffic(mut state) => {
+                while let Some(res) = state.next_record() {
+                    let AppDataRecord {
+                        discard: new_discard,
+                        payload,
+                    } = res?;
+                    discard += new_discard;
+
+                    if payload.starts_with(b"HTTP") {
+                        let response = core::str::from_utf8(payload)?;
+                        let header = response
+                            .lines()
+                            .next()
+                            .unwrap_or(response);
+
+                        println!("{header}");
+                    } else {
+                        println!("(.. continued HTTP response ..)");
+                    }
+
+                    received_response = true;
+                }
+            }
+
+            ConnectionState::EncodeTlsData(mut state) => {
+                try_or_resize_and_retry(
+                    |out_buffer| state.encode(out_buffer),
+                    |e| {
+                        if let EncodeError::InsufficientSize(is) = &e {
+                            Ok(*is)
+                        } else {
+                            Err(e.into())
+                        }
+                    },
+                    outgoing_tls,
+                    &mut outgoing_used,
+                )?;
+            }
+
+            ConnectionState::TransmitTlsData(mut state) => {
+                if let Some(mut may_encrypt) = state.may_encrypt_app_data() {
+                    encrypt_http_request(
+                        &mut sent_request,
+                        &mut may_encrypt,
+                        outgoing_tls,
+                        &mut outgoing_used,
+                    );
+                }
+
+                send_tls(&mut sock, outgoing_tls, &mut outgoing_used).await?;
+                state.done();
+            }
+
+            ConnectionState::BlockedHandshake { .. } => {
+                recv_tls(&mut sock, incoming_tls, &mut incoming_used).await?;
+            }
+
+            ConnectionState::WriteTraffic(mut may_encrypt) => {
+                if encrypt_http_request(
+                    &mut sent_request,
+                    &mut may_encrypt,
+                    outgoing_tls,
+                    &mut outgoing_used,
+                ) {
+                    send_tls(&mut sock, outgoing_tls, &mut outgoing_used).await?;
+                    recv_tls(&mut sock, incoming_tls, &mut incoming_used).await?;
+                } else if !received_response {
+                    // this happens in the TLS 1.3 case. the app-data was sent in the preceding
+                    // `TransmitTlsData` state. the server should have already written a
+                    // response which we can read out from the socket
+                    recv_tls(&mut sock, incoming_tls, &mut incoming_used).await?;
+                } else {
+                    try_or_resize_and_retry(
+                        |out_buffer| may_encrypt.queue_close_notify(out_buffer),
+                        |e| {
+                            if let EncryptError::InsufficientSize(is) = &e {
+                                Ok(*is)
+                            } else {
+                                Err(e.into())
+                            }
+                        },
+                        outgoing_tls,
+                        &mut outgoing_used,
+                    )?;
+                    send_tls(&mut sock, outgoing_tls, &mut outgoing_used).await?;
+                    open_connection = false;
+                }
+            }
+
+            ConnectionState::Closed => {
+                open_connection = false;
+            }
+
+            // other states are not expected in this example
+            _ => unreachable!(),
+        }
+
+        if discard != 0 {
+            assert!(discard <= incoming_used);
+
+            incoming_tls.copy_within(discard..incoming_used, 0);
+            incoming_used -= discard;
+
+            eprintln!("discarded {discard}B from `incoming_tls`");
+        }
+
+        iter_count += 1;
+        assert!(
+            iter_count < MAX_ITERATIONS,
+            "did not get a HTTP response within {MAX_ITERATIONS} iterations"
+        );
+    }
+
+    assert!(sent_request);
+    assert!(received_response);
+    assert_eq!(0, incoming_used);
+    assert_eq!(0, outgoing_used);
+
+    Ok(())
+}
+
+fn try_or_resize_and_retry<E>(
+    mut f: impl FnMut(&mut [u8]) -> Result<usize, E>,
+    map_err: impl FnOnce(E) -> Result<InsufficientSizeError, Box<dyn Error>>,
+    outgoing_tls: &mut Vec<u8>,
+    outgoing_used: &mut usize,
+) -> Result<usize, Box<dyn Error>>
+where
+    E: Error + 'static,
+{
+    let written = match f(&mut outgoing_tls[*outgoing_used..]) {
+        Ok(written) => written,
+
+        Err(e) => {
+            let InsufficientSizeError { required_size } = map_err(e)?;
+            let new_len = *outgoing_used + required_size;
+            outgoing_tls.resize(new_len, 0);
+            eprintln!("resized `outgoing_tls` buffer to {new_len}B");
+
+            f(&mut outgoing_tls[*outgoing_used..])?
+        }
+    };
+
+    *outgoing_used += written;
+
+    Ok(written)
+}
+
+async fn recv_tls(
+    sock: &mut TcpStream,
+    incoming_tls: &mut [u8],
+    incoming_used: &mut usize,
+) -> Result<(), Box<dyn Error>> {
+    let read = sock
+        .read(&mut incoming_tls[*incoming_used..])
+        .await?;
+    eprintln!("received {read}B of data");
+    *incoming_used += read;
+    Ok(())
+}
+
+async fn send_tls(
+    sock: &mut TcpStream,
+    outgoing_tls: &[u8],
+    outgoing_used: &mut usize,
+) -> Result<(), Box<dyn Error>> {
+    sock.write_all(&outgoing_tls[..*outgoing_used])
+        .await?;
+    eprintln!("sent {outgoing_used}B of data");
+    *outgoing_used = 0;
+    Ok(())
+}
+
+fn encrypt_http_request(
+    sent_request: &mut bool,
+    may_encrypt: &mut WriteTraffic<'_, ClientConnectionData>,
+    outgoing_tls: &mut [u8],
+    outgoing_used: &mut usize,
+) -> bool {
+    if !*sent_request {
+        let request = format!("GET / HTTP/1.1\r\nHost: {SERVER_NAME}\r\nConnection: close\r\nAccept-Encoding: identity\r\n\r\n").into_bytes();
+        let written = may_encrypt
+            .encrypt(&request, &mut outgoing_tls[*outgoing_used..])
+            .expect("encrypted request does not fit in `outgoing_tls`");
+        *outgoing_used += written;
+        *sent_request = true;
+        eprintln!("queued HTTP request");
+        true
+    } else {
+        false
+    }
+}