code: func NewMedianTime() MedianTimeSource {
  	return &medianTime{
  		knownIDs: make(map[string]struct{}),
  		offsets:  make([]int64, 0, maxMedianTimeEntries),
  	}
  }
docs: // NewMedianTime returns a new instance of concurrency-safe implementation of
  // the MedianTimeSource interface.  The returned implementation contains the
  // rules necessary for proper time handling in the chain consensus rules and
  // expects the time samples to be added from the timestamp field of the version
  // message received from remote peers that successfully connect and negotiate.