Delays program execution for the given number of seconds and nanoseconds.
Must be a non-negative integer.
Must be a non-negative integer less than 1 billion.
On Windows, the system may sleep longer that the given number of nanoseconds, depending on the hardware.
Returns true on success or false on failure.
If the delay was interrupted by a signal, an associative array will be returned with the components:
seconds - number of seconds remaining in the delay
nanoseconds - number of nanoseconds remaining in the delay