scripts: add script that broadcasts tx to lots of servers

useful when trying to RBF a tx that did not opt-in to RBF

electrum/scripts/txbroadcast.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+#
+# Connect to lots of servers and broadcast a given tx to each.
+
+import sys
+import asyncio
+
+from electrum.network import filter_protocol, Network
+from electrum.util import create_and_start_event_loop, log_exceptions
+from electrum.simple_config import SimpleConfig
+
+
+try:
+    rawtx = sys.argv[1]
+except:
+    print("usage: txbroadcast rawtx")
+    sys.exit(1)
+
+config = SimpleConfig()
+
+loop, stopping_fut, loop_thread = create_and_start_event_loop()
+network = Network(config)
+network.start()
+
+@log_exceptions
+async def f():
+    try:
+        peers = await network.get_peers()
+        peers = filter_protocol(peers)
+        results = await network.send_multiple_requests(peers, 'blockchain.transaction.broadcast', [rawtx])
+        for server, resp in results.items():
+            print(f"result: server={server}, response={resp}")
+    finally:
+        stopping_fut.set_result(1)
+
+asyncio.run_coroutine_threadsafe(f(), loop)