Block on last sequence message

[bmistree]

An endpoint that sends a message to another endpoint in a sequence blocks on that sequence's completion of that message before resuming operation. Eg.,

Sequence Example()
{
EndA.first{}
EndB.second{}
}

In this case, EndA will not proceed until it receives a message back from EndB that second has completed. This is despite the fact that EndA's further execution does not depend on any data from EndB. In these cases (ie, where data are not exchanged/modified), write a short-circuit that allows EndA to proceed.