Stopwatch for MPI

It is often important to time operations in MPI. The Stopwatch object will do that for you by recording the current MPI time (with MPI.Wtime) when you ask for a "stamp" given a label. The "start" stamp is recorded automatically when the Stopwatch is created. You add more stamps with the stamp function. If you want to transport the Stopwatch over MPI, then you can turn it into a NamedTuple with asNamedTuple (the NamedTuple will be isbits compatible).

# Note that this block is not run because it crashes the GitHub Action
# that generates the documentation. I think this happens because
# MPI.Wtime is called.  So this sketch of what to do will have
# to suffice

using IRMA

sw = Stopwatch()  # The start stamp is automatically recorded

# Do stuff
sleep(0.2)
stamp(sw, "A")

# Do more stuff
sleep(0.2)
stamp(sw, "B")

# Now we want to do MPI.Gather or something similar
nt = asNamedTuple(sw)
# allTimes = MPI.Gather(nt, root, comm)