Mark OLESEN authored Mar 03, 2022 and Andrew Heather committed Mar 04, 2022

- the internal data are contiguous so can broadcast size and internals
  directly without an intermediate stream.

ENH: split out broadcast time for profilingPstream information

STYLE: minor Pstream cleanup

- UPstream::commsType_ from protected to private, since it already has
  inlined noexcept getters/setters that should be used.

- don't pass unused/unneed tag into low-level MPI reduction templates.
  Document where tags are not needed

- had Pstream::broadcast instead of UPstream::broadcast in internals