LWT is much more efficient if a request is processed on a shard that owns
a token for the request. This is because otherwise the processing will
bounce to an owning shard multiple times. The patch proposes a way to
move request to correct shard before running lwt. It works by returning
an error from lwt code if a shard is incorrect one specifying the shard
the request should be moved to. The error is processed by transport code
that jumps to a correct shard and re-process incoming message there.
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