function OneToManyIterator() {
	    var _this16;

	    _this16 = _LazyIterator11.call(this) || this;
	    _this16.outputQueue = new GrowingRingBuffer();
	    _this16.lastRead = Promise.resolve({
	      value: null,
	      done: false
	    });
	    return _this16;
	  }
A base class for transforming streams that operate by maintaining an
output queue of elements that are ready to return via next().  This is
commonly required when the transformation is 1-to-many:  A call to next()
may trigger a call to the underlying stream, which will produce many
mapped elements of this stream-- of which we need to return only one, so
we have to queue the rest.