Add a session accessor to the client.

src/lib.rs

@@ -80,6 +80,17 @@ impl Client<HttpConnector> {
             session: Mutex::new(session),
         }))
     }
+
+    /// Get a copy of the current `Session`, if any.
+    ///
+    /// Useful for serializing and persisting the session to be restored later.
+    pub fn session(&self) -> Option<Session> {
+        self.0
+            .session
+            .lock()
+            .expect("session mutex was poisoned")
+            .clone()
+    }
 }
 
 #[cfg(feature = "tls")]