Make sure all data is written to socket

Using `write` means that it's possible that not all data gets written
out. Rather than check the return value and write in a loop, just use
`write_all`.

src/main.rs

@@ -33,7 +33,7 @@ fn read_body<T: Read + Write>(length: u32, socket: &mut ProxySocket<T>) {
 
     if let Ok(_) = handle.read_exact(&mut buffer) {
         if valid_length(length) {
-            socket.write(&buffer).unwrap();
+            socket.write_all(&buffer).unwrap();
             socket.flush().unwrap();
             read_response(socket);
         }
@@ -52,7 +52,7 @@ fn write_response(buf: &[u8]) {
     let mut out = stdout.lock();
 
     out.write_u32::<NativeEndian>(buf.len() as u32).unwrap();
-    out.write(buf).unwrap();
+    out.write_all(buf).unwrap();
     out.flush().unwrap();
 }