TimerHandle.when() segfaults if called after callback #468

• uvloop version: uvloop==0.16.0
• Python version: 3.10.4
• Platform: Linux-5.17.5-200.fc35.x86_64-x86_64-with-glibc2.34
• Can you reproduce the bug with PYTHONASYNCIODEBUG in env?: Yes
• Does uvloop behave differently from vanilla asyncio? How?: It segfaults.

Calling when() on a TimerHandle object after callback has been executed causes a core dump.

import uvloop
import asyncio


async def main():
    loop = asyncio.get_running_loop()
    timer = loop.call_later(0.1, lambda: None) # call any function
    await asyncio.sleep(0.2)
    timer.when() # segfault happens here
    
uvloop.install()
asyncio.run(main())