Re-merge Wait for handlers to exit when stopping gRPC server
With #5953 (closed) resolved by !6841 (merged), we can now re-merge !6784 (merged).
Revert the revert MR, !6803 (merged)
With #5953 (closed) resolved by !6841 (merged), we can now re-merge !6784 (merged).
Revert the revert MR, !6803 (merged)