code: func (m *meta) validate() error {
  	if m.magic != magic {
  		return ErrInvalid
  	} else if m.version != version {
  		return ErrVersionMismatch
  	} else if m.checksum != 0 && m.checksum != m.sum64() {
  		return ErrChecksum
  	}
  	return nil
  }
docs: // validate checks the marker bytes and version of the meta page to ensure it matches this binary.