NetToChainAdapter

即可以被动接受数据；

也可以主动发送请求，然后接受数据。

total_difficulty

total_height

transaction_received

block_received

compact_block_received

header_received

headers_received

locate_headers

get_block

txhashset_read

txhashset_receive_ready

txhashset_write

new

init

find_common_header

process_block

validate_chain

check_compact

request_block

request_block_by_hash

request_compact_block

send_block_request_to_peer

chain_opts