class virtual poll_based :object..end
method private virtual poll : (Unix.file_descr * bool * bool) list ->
float -> (Unix.file_descr * bool * bool) listpoll fds tiomeout, where fds is a list of tuples of the
form (fd, check_readable, check_writable), waits for either:
check_readable set to
true to become readablecheck_writable set to
true to become writable