Fixed the bug that the handler cannot get the main thread context on the Windows platform.

[bestcondition]

platform

windows

minimal reproducible demo

import tornado.ioloop
import tornado.web

import contextvars

v = contextvars.ContextVar('v', default='default')


# Define a request handler
class MainHandler(tornado.web.RequestHandler):
    def get(self):
        print(v.get())
        self.write("Hello, World!")


# Define the application
def make_app():
    return tornado.web.Application([
        (r"/", MainHandler),
    ])


# Start the server
if __name__ == "__main__":
    v.set('foo')
    app = make_app()
    app.listen(8888)  # Listen on port 8888
    print("Server is running on http://localhost:8888")
    tornado.ioloop.IOLoop.current().start()

Run and visit http://localhost:8888, then print default

[bestcondition]

@bdarnell , hello! My pull request has been open for a while, and I would appreciate it if you could take a look. Thank you very much for your contributions to this project! I look forward to your feedback.

[bdarnell]

Thanks and sorry for the delay. The change looks good, but would you mind adding a simple test case for it?