Obtains and ignores the next task that the executor
would otherwise execute, if one is immediately available,
and then retries execution of task r, unless the executor
is shut down, in which case task r is instead discarded.
@param r the runnable task requested to be executed
@param e the executor attempting to execute this task
Obtains and ignores the next task that the executor would otherwise execute, if one is immediately available, and then retries execution of task r, unless the executor is shut down, in which case task r is instead discarded.
@param r the runnable task requested to be executed @param e the executor attempting to execute this task