This pull request includes several changes to improve the handling of server shutdowns and enhance test coverage for both gRPC and HTTP servers. The most important changes include modifications to the server shutdown logic, the addition of new tests, and synchronization improvements in the test code.

Improvements to server shutdown logic:

• transport/grpc/server.go: Modified the Stop method to perform a force stop if the server cannot stop gracefully within the given context timeout.
• transport/http/server.go: Updated the Stop method to log a warning and perform a force stop if the server cannot shut down gracefully within the context timeout.

Addition of new tests:

• transport/grpc/server_test.go: Added a new TestStop function to test the gRPC server's ability to handle graceful and forceful shutdowns.
• transport/http/server_test.go: Added a new TestStop function to test the HTTP server's ability to handle graceful and forceful shutdowns.

Synchronization improvements in test code:

• transport/http/resolver_test.go: Added synchronization mechanisms to mockWatch methods to ensure thread safety during tests. [1] [2] [3]

These changes aim to enhance the robustness of server shutdown processes and improve the reliability of tests.