- looks like around python3.9, they changed it so that
if we don't block on the main thread, it starts to shut things down
- polling thread.join() makes Ctrl+C work. kind of.
```
$ ./electrum/scripts/txradar.py 6bde84a981e72573666fcc51c81ec3f8f4a813709bf16451dce3f106a114d392
Exception in run: RuntimeError('cannot schedule new futures after interpreter shutdown')
Traceback (most recent call last):
File "/home/user/wspace/electrum/electrum/util.py", line 1218, in wrapper
return await func(*args, **kwargs)
File "/home/user/wspace/electrum/electrum/interface.py", line 649, in wrapper_func
return await func(self, *args, **kwargs)
File "/home/user/wspace/electrum/electrum/interface.py", line 675, in run
await self.open_session(ssl_context=ssl_context)
File "/home/user/wspace/electrum/electrum/interface.py", line 872, in open_session
async with _RSClient(
File "/home/user/.local/lib/python3.10/site-packages/aiorpcx/rawsocket.py", line 167, in __aenter__
_transport, protocol = await self.create_connection()
File "/home/user/wspace/electrum/electrum/interface.py", line 285, in create_connection
return await super().create_connection()
File "/home/user/.local/lib/python3.10/site-packages/aiorpcx/rawsocket.py", line 163, in create_connection
return await connector.create_connection(
File "/usr/lib/python3.10/asyncio/base_events.py", line 1036, in create_connection
infos = await self._ensure_resolved(
File "/usr/lib/python3.10/asyncio/base_events.py", line 1418, in _ensure_resolved
return await loop.getaddrinfo(host, port, family=family, type=type,
File "/usr/lib/python3.10/asyncio/base_events.py", line 863, in getaddrinfo
return await self.run_in_executor(
File "/usr/lib/python3.10/asyncio/base_events.py", line 821, in run_in_executor
executor.submit(func, *args), loop=self)
File "/usr/lib/python3.10/concurrent/futures/thread.py", line 169, in submit
raise RuntimeError('cannot schedule new futures after '
RuntimeError: cannot schedule new futures after interpreter shutdown
```
Previously all the interfaces used either "t" or "s".
Now the network only tries to use "s" for all interfaces, except for
the main interface, which the user can manually specify to use "t".
(so e.g. if you run with "--server localhost:50002:t", the main server will use "t",
but all the rest will use "s")
