Right now, the streamable client connection retries broken resumable connections up to StreamableClientTransport.MaxRetries, but once a connection has been re-established, the counter resets.

This can lead to a failure mode where a server keeps terminating the connection with status 200. We should either:

1. Set a global limit on the number of retries across a single logical stream.
2. Only reset the retry counter when the Last-Event-ID actually makes progress.

I'm leaning toward 2: if the stream is active and long-running, a global limit could be problematic. On the other hand, (2) doesn't have that problem, and still avoids the degenerate failure mode.

CC @jba @markus-kusano