Remove Sync bound from TlsConnector io arg

src/lib.rs

@@ -364,7 +364,7 @@ pub(crate) fn default_tls_config() -> std::sync::Arc<dyn TlsConnector> {
         fn connect(
             &self,
             _dns_name: &str,
-            _io: Box<dyn ReadWrite + Sync>,
+            _io: Box<dyn ReadWrite>,
         ) -> Result<Box<dyn ReadWrite>, crate::error::Error> {
             Err(ErrorKind::UnknownScheme
                 .msg("cannot make HTTPS request because no TLS backend is configured"))

src/ntls.rs

@@ -11,11 +11,7 @@ pub(crate) fn default_tls_config() -> std::sync::Arc<dyn TlsConnector> {
 }
 
 impl TlsConnector for native_tls::TlsConnector {
-    fn connect(
-        &self,
-        dns_name: &str,
-        io: Box<dyn ReadWrite + Sync>,
-    ) -> Result<Box<dyn ReadWrite>, Error> {
+    fn connect(&self, dns_name: &str, io: Box<dyn ReadWrite>) -> Result<Box<dyn ReadWrite>, Error> {
         let stream =
             native_tls::TlsConnector::connect(self, dns_name, io).map_err(|e| match e {
                 native_tls::HandshakeError::Failure(e) => ErrorKind::ConnectionFailed
@@ -31,7 +27,7 @@ impl TlsConnector for native_tls::TlsConnector {
 }
 
 #[cfg(feature = "native-tls")]
-impl ReadWrite for native_tls::TlsStream<Box<dyn ReadWrite + Sync>> {
+impl ReadWrite for native_tls::TlsStream<Box<dyn ReadWrite>> {
     fn socket(&self) -> Option<&TcpStream> {
         self.get_ref().socket()
     }

src/rtls.rs

@@ -27,7 +27,7 @@ fn is_close_notify(e: &std::io::Error) -> bool {
     false
 }
 
-struct RustlsStream(rustls::StreamOwned<rustls::ClientConnection, Box<dyn ReadWrite + Sync>>);
+struct RustlsStream(rustls::StreamOwned<rustls::ClientConnection, Box<dyn ReadWrite>>);
 
 impl ReadWrite for RustlsStream {
     fn socket(&self) -> Option<&TcpStream> {
@@ -97,7 +97,7 @@ impl TlsConnector for Arc<rustls::ClientConfig> {
     fn connect(
         &self,
         dns_name: &str,
-        mut io: Box<dyn ReadWrite + Sync>,
+        mut io: Box<dyn ReadWrite>,
     ) -> Result<Box<dyn ReadWrite>, Error> {
         let sni = rustls::ServerName::try_from(dns_name)
             .map_err(|e| ErrorKind::Dns.msg(format!("parsing '{}'", dns_name)).src(e))?;

src/stream.rs

@@ -42,7 +42,7 @@ pub trait TlsConnector: Send + Sync {
     fn connect(
         &self,
         dns_name: &str,
-        io: Box<dyn ReadWrite + Sync>,
+        io: Box<dyn ReadWrite>,
     ) -> Result<Box<dyn ReadWrite>, crate::error::Error>;
 }