AudioBufferSourceNode issues

-- In start(), what happens if 'buffer' is null?
-- In start(), what happens if 'offset' is negative? What if it's greater
then the duration of the buffer?
-- In start(), what happens if 'offset' + 'duration' is greater than the
duration of the buffer?
-- In stop(), the text says "stop must only be called one time and only
after a call to start or stop, or an exception will be thrown." So stop()
can be called multiple times? What happens in that case ... does a second
call to stop() completely override the first stop() time? What happens if
playback has already stopped due to the first stop() call?

Thanks,
Rob
-- 
Jesus called them together and said, “You know that the rulers of the
Gentiles lord it over them, and their high officials exercise authority
over them. Not so with you. Instead, whoever wants to become great among
you must be your servant, and whoever wants to be first must be your
slave — just
as the Son of Man did not come to be served, but to serve, and to give his
life as a ransom for many.” [Matthew 20:25-28]