Respond to upstream

Author: dandavison

tests/nexus/test_handler.py

@@ -30,7 +30,6 @@
 import pytest
 from google.protobuf import json_format
 from nexusrpc.testing.client import ServiceClient
-from typing_extensions import Never
 
 import temporalio.api.failure.v1
 import temporalio.nexus
@@ -72,7 +71,7 @@ class MyService:
     # echo_renamed: nexusrpc.Operation[Input, Output] = (
     #     nexusrpc.Operation(name="echo-renamed")
     # )
-    hang: nexusrpc.Operation[Input, Never]
+    hang: nexusrpc.Operation[Input, Output]
     log: nexusrpc.Operation[Input, Output]
     async_operation: nexusrpc.Operation[Input, Output]
     async_operation_without_type_annotations: nexusrpc.Operation[Input, Output]
@@ -129,8 +128,9 @@ async def echo(
     @nexusrpc.handler.sync_operation_handler
     async def hang(
         self, ctx: nexusrpc.handler.StartOperationContext, input: Input
-    ) -> Never:
+    ) -> Output:
         await asyncio.Future()
+        return Output(value="won't reach here")
 
     @nexusrpc.handler.sync_operation_handler
     async def non_retryable_application_error(