feat: support progress_callback propagation in ClientSession (issue #1248)

Author: nkaushal99

src/mcp/client/session.py

@@ -112,6 +112,7 @@ def __init__(
         read_stream: MemoryObjectReceiveStream[SessionMessage | Exception],
         write_stream: MemoryObjectSendStream[SessionMessage],
         read_timeout_seconds: timedelta | None = None,
+        progress_callback: ProgressFnT | None = None,
         sampling_callback: SamplingFnT | None = None,
         elicitation_callback: ElicitationFnT | None = None,
         list_roots_callback: ListRootsFnT | None = None,
@@ -127,6 +128,7 @@ def __init__(
             read_timeout_seconds=read_timeout_seconds,
         )
         self._client_info = client_info or DEFAULT_CLIENT_INFO
+        self._progress_callback = progress_callback
         self._sampling_callback = sampling_callback or _default_sampling_callback
         self._elicitation_callback = elicitation_callback or _default_elicitation_callback
         self._list_roots_callback = list_roots_callback or _default_list_roots_callback
@@ -302,7 +304,7 @@ async def call_tool(
             ),
             types.CallToolResult,
             request_read_timeout_seconds=read_timeout_seconds,
-            progress_callback=progress_callback,
+            progress_callback=progress_callback or self._progress_callback,
         )
 
         if not result.isError: