Use `std:🧵:available_parallelism` in place of num_cpus (#199)

Cargo.toml

@@ -18,7 +18,6 @@ raw-api = []
 send_guard = ["parking_lot/send_guard"]
 
 [dependencies]
-num_cpus = "1.13.1"
 parking_lot = "0.12.0"
 hashbrown = "0.11.2"
 serde = { version = "1.0.136", optional = true, features = ["derive"] }

rust-toolchain

@@ -1,4 +1,4 @@
 [toolchain]
-channel = "stable-2020-12-31"
+channel = "1.59"
 components = [ "rustfmt", "clippy" ]
 profile = "minimal"

src/lib.rs

@@ -46,7 +46,7 @@ cfg_if! {
 pub(crate) type HashMap<K, V, S> = hashbrown::HashMap<K, SharedValue<V>, S>;
 
 fn default_shard_amount() -> usize {
-    (num_cpus::get() * 4).next_power_of_two()
+    (std::thread::available_parallelism().map_or(1, usize::from) * 4).next_power_of_two()
 }
 
 fn ncb(shard_amount: usize) -> usize {