Problem: filter api missing events when internal websocket client reconnect

[yihuang]

@mmsqe found that the reason for the mempool test failure is due to internal ws connection reconnect occasionally, when that happens, the API lose messages.

[mmsqe]

since No way to detect data loss based on current desgin, not sure if we can deprecate websocket and switch to long poll on events endpoint with after cursor, starting 1st perf improve, need backport rest one by one

[yihuang]

since No way to detect data loss based on current desgin, not sure if we can deprecate websocket and switch to long poll on events endpoint with after cursor, starting 1st perf improve

yeah, that's the plan tendermint/tendermint#9305