Submits a one-shot task that becomes enabled after the given delay.
@param command the task to execute
@param delay the time from now to delay execution
@param unit the time unit of the delay parameter
@return a ScheduledFuture representing pending completion of
the task and whose {@code get()} method will return
{@code null} upon completion
@throws RejectedExecutionException if the task cannot be
scheduled for execution
@throws NullPointerException if command or unit is null
Submits a one-shot task that becomes enabled after the given delay.
@param command the task to execute @param delay the time from now to delay execution @param unit the time unit of the delay parameter @return a ScheduledFuture representing pending completion of the task and whose {@code get()} method will return {@code null} upon completion @throws RejectedExecutionException if the task cannot be scheduled for execution @throws NullPointerException if command or unit is null