Add blockHash option to eth_getLogs (EIP 234)

[fabioberger]

As described in EIP 234, eth_getLogs currently only supports querying logs by block number and not block hash.

This makes it impossible to know whether the logs returned are from the expected block, or if a block-reorg happened and the logs returned are actually from another block. Help!

Since the EIP's acceptance, the blockHash param has been added to the official Ethereum JSON RPC docs.

Geth also recently implemented EIP 234 (ethereum/go-ethereum#16734), would it be possible for Parity to do the same?

Getting a reliable stream of logs, regardless of re-orgs is not possible without this change.

[avonian]

this is a serious problem affecting my projects as well

[MicahZoltu]

Killing Augur at the moment as well.

[nionis]

EIP 234 helps alot with quarantining consistency of state due to reorgs when using indexers, right now the only alternative has a bandwidth trade off

[jam10o-new]

I'm assuming this issue has been addressed by #9256? Correct me otherwise.