Add support for alternate TLs implementations.

src/ntls.rs

@@ -0,0 +1,30 @@
+use crate::error::Error;
+use crate::error::ErrorKind;
+use crate::stream::{HttpsStream, TlsConnector};
+
+use std::net::TcpStream;
+use std::sync::Arc;
+
+#[allow(dead_code)]
+pub(crate) fn default_tls_config() -> std::sync::Arc<dyn TlsConnector> {
+    Arc::new(native_tls::TlsConnector::new().unwrap())
+}
+
+impl TlsConnector for native_tls::TlsConnector {
+    fn connect(
+        &self,
+        dns_name: &str,
+        tcp_stream: TcpStream,
+    ) -> Result<Box<dyn HttpsStream>, Error> {
+        let stream = native_tls::TlsConnector::connect(self, dns_name, tcp_stream)
+            .map_err(|e| ErrorKind::Dns.new().src(e))?;
+        Ok(Box::new(stream))
+    }
+}
+
+#[cfg(feature = "native-tls")]
+impl HttpsStream for native_tls::TlsStream<TcpStream> {
+    fn socket(&self) -> Option<&TcpStream> {
+        Some(self.get_ref())
+    }
+}