Effects: Atomically transfers the associated output of *this
to the stream buffer *wrapped,
so that it appears in the output stream
as a contiguous sequence of characters.
wrapped->pubsync() is called
if and only if a call was made to sync()
since the most recent call to emit(), if any.
Synchronization: All emit() calls transferring characters
to the same stream buffer object
appear to execute in a total order
consistent with the โhappens beforeโ relation ([intro.races]),
where each emit() call
synchronizes with
subsequent emit() calls in that total order.