Remove unnecessary intermediate allocations

src/client/builder.rs

@@ -505,8 +505,7 @@ impl<'u> ClientBuilder<'u> {
 	{
 		// send request
 		let resource = self.build_request();
-		let data = format!("GET {} {}\r\n{}\r\n", resource, self.version, self.headers);
-		stream.write_all(data.as_bytes())?;
+		write!(stream, "GET {} {}\r\n{}\r\n", resource, self.version, self.headers)?;
 
 		// wait for a response
 		let mut reader = BufReader::new(stream);

src/result.rs

@@ -83,11 +83,11 @@ impl fmt::Display for WebSocketOtherError {
 			WebSocketOtherError::ProtocolError(e) => write!(fmt, "WebSocketError: {}", e),
 			#[cfg(any(feature = "sync-ssl", feature = "async-ssl"))]
 			WebSocketOtherError::TlsHandshakeFailure => {
-				write!(fmt, "WebSocketError: {}", "TLS Handshake failure")
+				fmt.write_str("WebSocketError: TLS Handshake failure")
 			}
 			#[cfg(any(feature = "sync-ssl", feature = "async-ssl"))]
 			WebSocketOtherError::TlsHandshakeInterruption => {
-				write!(fmt, "WebSocketError: {}", "TLS Handshake interrupted")
+				fmt.write_str("WebSocketError: TLS Handshake interrupted")
 			}
 		}
 	}

src/server/mod.rs

@@ -55,9 +55,9 @@ where
 {
 	fn fmt(&self, fmt: &mut Formatter<'_>) -> FmtResult {
 		fmt.debug_struct("InvalidConnection")
-			.field("stream", &String::from("..."))
-			.field("parsed", &String::from("..."))
-			.field("buffer", &String::from("..."))
+			.field("stream", &"...")
+			.field("parsed", &"...")
+			.field("buffer", &"...")
 			.field("error", &self.error)
 			.finish()
 	}

src/server/upgrade/mod.rs

@@ -135,12 +135,7 @@ where
 
 	#[cfg(feature = "sync")]
 	fn send(&mut self, status: StatusCode) -> io::Result<()> {
-		let data = format!(
-			"{} {}\r\n{}\r\n",
-			self.request.version, status, self.headers
-		);
-		self.stream.write_all(data.as_bytes())?;
-		Ok(())
+		write!(self.stream, "{} {}\r\n{}\r\n", self.request.version, status, self.headers)
 	}
 
 	#[doc(hidden)]

websocket-base/src/header.rs

@@ -101,11 +101,10 @@ impl FromStr for WebSocketAccept {
 impl WebSocketAccept {
 	/// Create a new WebSocketAccept from the given WebSocketKey
 	pub fn new(key: &WebSocketKey) -> WebSocketAccept {
-		let serialized = key.serialize();
-		let mut concat_key = String::with_capacity(serialized.len() + 36);
-		concat_key.push_str(&serialized[..]);
-		concat_key.push_str(MAGIC_GUID);
-		let hash = Sha1::digest(concat_key.as_bytes());
+		let mut serialized = key.serialize();
+		serialized.reserve_exact(MAGIC_GUID.len());
+		serialized.push_str(MAGIC_GUID);
+		let hash = Sha1::digest(serialized.as_bytes());
 		WebSocketAccept(hash.into())
 	}
 	/// Return the Base64 encoding of this WebSocketAccept

websocket-base/src/message.rs

@@ -166,7 +166,7 @@ impl<'a> ws::dataframe::DataFrame for Message<'a> {
 			let mut buf = Vec::with_capacity(2 + self.payload.len());
 			buf.write_u16::<BigEndian>(reason)
 				.expect("failed to write close code in take_payload");
-			buf.append(&mut self.payload.into_owned());
+			buf.extend_from_slice(&self.payload);
 			buf
 		} else {
 			self.payload.into_owned()