Aeron - choose short virtual peer id using a hash of the virtual peer id

[lbradstreet]

The Aeron messaging component chooses the short int dispatch id in a consistent way by choosing the next value from a set of shorts. This means that shorts may be quickly reused when they are deallocated. A better solution would be to choose these via a hash of the id, mod to the range of a short. If the short is used by another vpeer on that instance, rehash the hashed id, and mod again.

This reduces chance that a new vpeer will receive messages from a peer that was just shutdown. Note, this was also a problem with the port allocation scheme, though it probably wouldn't have ever happened in practice.

[lbradstreet]

Closed by @dignati in #280