Consider implementing publish flow control

When a streaming connection to the pub/sub lite service is started, an InitialRequest is sent to establish the stream. Typically, we wait until an initial response is received before the stream enters the "running" state.

However, if the InitialRequest fails due to a retryable error, the connection is retried and the stream enters the "running" state before an initial response has been received.

Start by tracing the publish streaming connection from InitialRequest through retry handling and the transition to the "running" state. Confirm the current behavior with a focused test, then ensure a retryable initial failure does not mark the stream running before an initial response is received.

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