sb: compile-time option for routing table as a hash

[skliper]

We've discussed how to handle a large number of subscriptions, one option would be to have the RoutingTbl be a hash instead.

This does have a performance impact on code that is heavily used, but in some environments memory is less of a concern so a large hash table could support a very large subscription base.

While I don't feel it would be wise to switch whole-hog, I propose that a compile-time option be available to configure the software bus to use a hash for the routing table, which gives users with larger subscription needs the option.

[skliper]

Imported from trac issue 186. Created by cdknight on 2017-03-21T15:16:08, last modified: 2019-03-01T15:27:58

[skliper]

OBE - routing table entries are no longer freed when there are no subscribers, and adding deconfliction information to the destination block would be a net higher cost in memory. Closing as invalid per the current design.