discard dodgy thrift connections, thread-safe pooling

I had issues using elasticsearch-py and ThriftConnection in connection with threads as well as greenlets.
At some point, thrift connections seem to go into a weird state, and you end up getting responses for requests sent from another thread and vice versa.
so you are not releasing connections that threw exception? How will they get closed? Do we care? (no idea, just pondering out loud)