code: func (e *RawV4Event) VariableLengthData() []byte {
  	begin := (sizeOfBasicV4EventHeader +
  		e.extraHeadersSize +
  		e.fixedLengthDataSize)
  	end := len(e.data) - e.checksumSize
  	return e.data[begin:end]
  }
docs: // VariableLengthData returns the variable length data associated to the event.
  // By default, the variable length data also include the extra headers, the
  // fixed length data and the optional checksum footer.