feat: Allow reading the configuration.

This allows wrapper types to correctly split data before creating websocket
messages, guaranteeing to respect the max size.

Notably when the WebSocket is provided by user code.

src/protocol/mod.rs

@@ -111,6 +111,11 @@ impl<Stream> WebSocket<Stream> {
         self.context.set_config(set_func)
     }
 
+    /// Read the configuration.
+    pub fn get_config(&self) -> &WebSocketConfig {
+        self.context.get_config()
+    }
+
     /// Check if it is possible to read messages.
     ///
     /// Reading is impossible after receiving `Message::Close`. It is still possible after
@@ -254,6 +259,11 @@ impl WebSocketContext {
         set_func(&mut self.config)
     }
 
+    /// Read the configuration.
+    pub fn get_config(&self) -> &WebSocketConfig {
+        &self.config
+    }
+
     /// Check if it is possible to read messages.
     ///
     /// Reading is impossible after receiving `Message::Close`. It is still possible after