Description
A few big problems:
1. Client will hang if submitting a request after close()
2. Multiple calls to close() hangs periodically
3. Closing the Cluster doesn't attempt to clean up open Client instances.
A few big problems:
1. Client will hang if submitting a request after close()
2. Multiple calls to close() hangs periodically
3. Closing the Cluster doesn't attempt to clean up open Client instances.