dtlog_pause() turns off all dtlog messages without detaching the
package, dtlog_resume() turns them back on. This is useful for a block of
code that would otherwise produce a lot of output.
Value
Invisibly the logging state before the call: TRUE if logging was
active, FALSE if it was paused. Both functions report the state they
found rather than the one they left behind, so dtlog_pause() returns
TRUE when it is the call that actually paused logging, and
dtlog_resume() returns FALSE when it is the call that actually
resumed it.