Force explicit tls configuration to connect to tls endpoint (#61)

Resolves #60.

Author: kezhuw

src/session/connection.rs

@@ -176,7 +176,6 @@ pub struct Connector {
 
 impl Connector {
     #[cfg(feature = "tls")]
-    #[allow(dead_code)]
     pub fn new() -> Self {
         Self { tls: None, timeout: Duration::from_secs(10) }
     }
@@ -210,7 +209,7 @@ impl Connector {
         if endpoint.tls {
             #[cfg(feature = "tls")]
             if self.tls.is_none() {
-                return Err(Error::new(ErrorKind::Unsupported, "tls not supported"));
+                return Err(Error::new(ErrorKind::Unsupported, "tls not configured"));
             }
             #[cfg(not(feature = "tls"))]
             return Err(Error::new(ErrorKind::Unsupported, "tls not supported"));

src/session/mod.rs

@@ -130,7 +130,10 @@ impl Builder {
             return Err(Error::BadArguments(&"connection timeout must not be negative"));
         }
         #[cfg(feature = "tls")]
-        let connector = Connector::with_tls(self.tls.unwrap_or_default().into_config()?);
+        let connector = match self.tls {
+            Some(options) => Connector::with_tls(options.into_config()?),
+            None => Connector::new(),
+        };
         #[cfg(not(feature = "tls"))]
         let connector = Connector::new();
         let (state_sender, state_receiver) = asyncs::sync::watch::channel(SessionState::Disconnected);