Fix async_end2end_test flow control

Completion queues + flow control + single threading is hard.

We need a read outstanding on a call to grant flow control tokens to the
remote end.

To do that we need to request a read *before* we wait for the write to
be finished, otherwise, in the case of a large write we'll block waiting
for flow control tokens.

Built on #6402

0 files changed, 0 insertions, 0 deletions