def __init__(self, clock=None):
self.clock = clock or _Clock()<EOL>self.current = collections.deque()<EOL>self.idlers = collections.deque()<EOL>self.inactive = <NUM_LIT:0>  <EOL>self.queue = []<EOL>self.rpcs = {}<EOL>
Constructor.

        Args:
          clock: an eventloop._Clock object. Defaults to a time-based clock.
        Fields:
          current: a FIFO list of (callback, args, kwds). These callbacks
            run immediately when the eventloop runs.
          idlers: a FIFO list of (callback, args, kwds). Thes callbacks
            run only when no other RPCs need to be fired first.
            For example, AutoBatcher uses idler to fire a batch RPC even before
            the batch is full.
          queue: a sorted list of (absolute time in sec, callback, args, kwds),
            sorted by time. These callbacks run only after the said time.
          rpcs: a map from rpc to (callback, args, kwds). Callback is called
            when the rpc finishes.