Copying more files over to 3.x branch from main. This includes
some connect/disconnect bug fixes we found in testing LCDS,
some additional hooks for throttling and messaging reliability
needed to compile/run LCDS next against 3.x
Also includes fix for LCDS-548 necessary for the DCD project.
LCDS-QE: yes - run LCDS test suite against this swc
Reviewers: all fixes reviewed when they went in on main