Add buffer method to MsgCounter
The Gaudi::Accumulators::MsgCounter
struct does not implement a buffer
method, unlike other accumulators.
a
buffer
is slightly tricky for a msgCounter, as in addition to accumulating some value, it should print something on the first N increments, and if you 'distribute' the increments, then it's not clear which are the first N, and you may end up (if you distribute it in M threads) with N*M messages in the worst case.