mtsSender has been simplified such that load and send are no longer called in Write. Load and Send have removed and logic is now in Write. The logic has been simplified such that it does not
try to send again. On next PR when ringbuffers are added to senders, we will add logic to deal with this.
Added a Write method to senders such that they implement io.Writer. The multiSender now takes a slice of io.writers.
Also modified revid code and tests to account for this chance.
Send retry has been removed from the multiSender. This also means there is not need for the active func, because we simply wait until the send is complete or failed to exit the output clips
routine. Tests pertinent to retrying or the active function have been removed.
Added test to check that if a sender is set to retry on send fails,
it will keep trying to send until it is successful, and have all
data that was intended to be written sent off.
Added a test in senders_test.go to check that we can give a multiSender a few senders and have it
write to them correctly when we call multSender.Write(). This involved writing a dummy
loadSender implementation called dummyLoadSender that stores what has been written to it so that
we can check at a later time.
Saxon