can be generated in a buffer and then sent to the frontend in a single
libpq call. This solves problems with NOTICE and ERROR messages generated
in the middle of a data message or COPY OUT operation.
where you state a format and arguments. the old behavior required
each appendStringInfo to have to have a sprintf() before it if any
formatting was required.
Also shortened several instances where there were multiple appendStringInfo()
calls in a row, doing nothing more then adding one more word to the String,
instead of doing them all in one call.
