code: func DefaultRinkebyGenesisBlock() *Genesis {
  	return &Genesis{
  		Config:     params.RinkebyChainConfig,
  		Timestamp:  1492009146,
  		ExtraData:  hexutil.MustDecode("0x52657370656374206d7920617574686f7269746168207e452e436172746d616e42eb768f2244c8811c63729a21a3569731535f067ffc57839b00206d1ad20c69a1981b489f772031b279182d99e65703f0076e4812653aab85fca0f00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
  		GasLimit:   4700000,
  		Difficulty: big.NewInt(1),
  		Alloc:      decodePrealloc(rinkebyAllocData),
  	}
  }
docs: // DefaultRinkebyGenesisBlock returns the Rinkeby network genesis block.