code: func (e *LogEntry) headerSize() int64 {
  	sz := uVarintSize(e.Length) + // total entry length
  		1 + // type
  		uVarintSize(uint64(len(e.Index))) + len(e.Index) + // Index length and data
  		uVarintSize(uint64(len(e.Field))) + len(e.Field) + // Field length and data
  		uVarintSize(uint64(len(e.IDs))) // ID/Key pair count
  	return int64(sz)
  }
docs: // headerSize returns the number of bytes required for size, type, index, field, & pair count.