rust-chg: reimplement attach_io operation as async function
In short, MessageLoop<Connection> was redesigned as Protocol<Connection>,
and the protocol methods no longer consume self.
API changes are briefly documented in the following page:
https://docs.rs/tokio-hglib/0.3.0/tokio_hglib/struct.Protocol.html
Differential Revision: https://phab.mercurial-scm.org/D8442
# An example WSGI for use with mod_wsgi, edit as necessary
# See https://mercurial-scm.org/wiki/modwsgi for more information
# Path to repo or hgweb config to serve (see 'hg help hgweb')
config = "/path/to/repo/or/config"
# Uncomment and adjust if Mercurial is not installed system-wide
# (consult "installed modules" path from 'hg debuginstall'):
#import sys; sys.path.insert(0, "/path/to/python/lib")
# Uncomment to send python tracebacks to the browser if an error occurs:
#import cgitb; cgitb.enable()
# enable demandloading to reduce startup time
from mercurial import demandimport; demandimport.enable()
from mercurial.hgweb import hgweb
application = hgweb(config)