les, light: LES/2 protocol version #14970
This PR implements the new LES protocol version extensions:
Yea - I think you are right - but perhaps I use a snapshot for once ;-) Would really love to see a faster light-client ..
This PR implements the new LES protocol version extensions: * new and more efficient Merkle proofs reply format (when replying to a multiple Merkle proofs request, we just send a single set of trie nodes containing all necessary nodes) * BBT (BloomBitsTrie) works similarly to the existing CHT and contains the bloombits search data to speed up log searches * GetTxStatusMsg returns the inclusion position or the pending/queued/unknown state of a transaction referenced by hash * an optional signature of new block data (number/hash/td) can be included in AnnounceMsg to provide an option for "very light clients" (mobile/embedded devices) to skip expensive Ethash check and accept multiple signatures of somewhat trusted servers (still a lot better than trusting a single server completely and retrieving everything through RPC). The new client mode is not implemented in this PR, just the protocol extension.