code: func NewMemDbBuffer(cap int) MemBuffer {
  	return &memDbBuffer{
  		db:              memdb.New(comparer.DefaultComparer, cap),
  		entrySizeLimit:  TxnEntrySizeLimit,
  		bufferLenLimit:  atomic.LoadUint64(&TxnEntryCountLimit),
  		bufferSizeLimit: TxnTotalSizeLimit,
  	}
  }
docs: // NewMemDbBuffer creates a new memDbBuffer.