messageComplete will send the receiving message to
start processing.
Any source argument will be ignored.
msg = .Message~new(.Array~new(1000)~fill(0)~allIndexes, "sort")
msg~notify(.Message~new(.stdout, "say", "I", "sorting complete"))
msg~notify(.Message~new(.r~new, "items", "I", msg))
msg~start
say "processing continues"
::class r
::method items
use strict arg m
say m~target~items "items sorted"
processing continues sorting complete 1000 items sorted