The CompactTxStreamer service did not implement any mempool RPC, so
lightwallets (SilentDragonXLite / ObsidianDragonLite) received UNIMPLEMENTED
from get_mempool_stream and permanently stopped their mempool monitor. As a
result the lite wallet could not see 0-confirmation transactions and only
surfaced incoming shielded chat messages after they were mined (~1 block).
Add GetMempoolStream(Empty) returns (stream RawTransaction). A single
process-wide monitor (frontend/mempool.go) polls the node's getrawmempool and
fetches each new tx via getrawtransaction (full serialized bytes, so shielded
memos are preserved -- CompactTx's 52-byte prefix would not carry a memo), then
fans the tx out to every subscribed stream. This avoids polling the node once
per connected wallet: N clients share one poll loop. The monitor starts lazily
on the first subscription, idles without touching the node when no clients are
connected, and closes all subscriber streams when a new block is mined (the
semantics the client's monitor loop expects; the client re-syncs and reconnects).
Purely additive and wire-compatible: RawTransaction field numbers and the
cash.z.wallet.sdk.rpc package match the deployed client; existing clients that
never call GetMempoolStream are unaffected.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
