feat: getters for Status Code & Data Length

Implements two methods on `Response` `struct`.

1. `status_code`
2. `data_length`

To act as "Getters" for these private properties in case they
are needed by the client.

src/response.rs

@@ -436,6 +436,16 @@ where
 
         Ok(())
     }
+
+    /// Retrieves the current value of the `Response` status code
+    pub fn status_code(&self) -> StatusCode {
+        self.status_code.clone()
+    }
+
+    /// Retrieves the current value of the `Response` data length
+    pub fn data_length(&self) -> Option<usize> {
+        self.data_length
+    }
 }
 
 impl<R> Response<R>