code: func (s *memSeries) reset() {
  	s.chunks = nil
  	s.headChunk = nil
  	s.firstChunkID = 0
  	s.nextAt = math.MinInt64
  	s.sampleBuf = [4]sample{}
  	s.pendingCommit = false
  	s.app = nil
  }
docs: // reset re-initialises all the variable in the memSeries except 'lset', 'ref',
  // and 'chunkRange', like how it would appear after 'newMemSeries(...)'.