code: func (b *MockConfigBlockBuilder) buildBlockMetadata() *common.BlockMetadata {
  	return &common.BlockMetadata{
  		Metadata: [][]byte{
  			b.buildSignaturesMetaDataBytes(),
  			marshalOrPanic(b.buildLastConfigMetaData()),
  			b.buildTransactionsFilterMetaDataBytes(),
  			b.buildOrdererMetaDataBytes(),
  		},
  	}
  }
docs: // buildBlockMetadata builds BlockMetadata that contains an array of bytes in the following order:
  // 	0: SIGNATURES
  // 	1: LAST_CONFIG
  // 	2: TRANSACTIONS_FILTER
  // 	3: ORDERER