ETH space only accept latest_state as block number.

ETH space only have pivot blocks as a list, and do not require to query non-pivot blocks.

EthAddress accepts both hex40 and base32 format addresses.

EthBlockNumber accepts number and epoch tag latest_state, other values are invalid, e.g.

EthBlockNumberOrHash accepts hex number, hash and epoch tag latest_state, other values are invalid, e.g.

EthCallRequest is compatible with CFX CallRequest and accepts hex40 format address.

EthLogFilter is compatible with CFX LogFilter and accepts hex40 format address.

TraceBuilder builds traces in stack way and thread unsafe.