Fix an issue which-in the service doesn't die when `../data/distwrite` doesn't exist. (#279)

Run RustFmt.

src/bastion/examples/distributed-fwrite.rs

@@ -1,6 +1,3 @@
-use bastion::prelude::*;
-#[cfg(not(target_os = "windows"))]
-use futures::*;
 #[cfg(not(target_os = "windows"))]
 use std::fs::File;
 use std::fs::OpenOptions;
@@ -9,6 +6,11 @@ use std::io::Write;
 use std::path::PathBuf;
 use std::sync::Arc;
 
+#[cfg(not(target_os = "windows"))]
+use futures::*;
+
+use bastion::prelude::*;
+
 ///
 /// Parallel (MapReduce) job which async writes results to a single output file
 ///
@@ -51,7 +53,6 @@ fn main() {
     // Get a shadowed sharable reference of workers.
     let workers = Arc::new(workers);
 
-    //
     // Mapper that generates work.
     Bastion::children(|children: Children| {
         children.with_exec(move |ctx: BastionContext| {
@@ -63,6 +64,11 @@ fn main() {
                 path.push("data");
                 path.push("distwrite");
 
+                if !path.exists() || !path.is_file() {
+                    Bastion::stop();
+                    panic!("The file could not be opened.");
+                }
+
                 let fo = OpenOptions::new()
                     .read(true)
                     .write(true)