FIFOSchedulableBuilder - SchedulableBuilder for FIFO Scheduling Mode

FIFOSchedulableBuilder is a SchedulableBuilder that holds a single Pool (that is given when FIFOSchedulableBuilder is created).

FIFOSchedulableBuilder is the default SchedulableBuilder for TaskSchedulerImpl.
When FIFOSchedulableBuilder is created, the TaskSchedulerImpl passes its own rootPool (a part of TaskScheduler Contract).

FIFOSchedulableBuilder obeys the SchedulableBuilder Contract as follows:

Creating FIFOSchedulableBuilder Instance

FIFOSchedulableBuilder takes the following when created: