Add BaseRequestHandler instance attributes (#384)
Add BaseRequestHandler instance attributes (#384)

From the BaseRequestHandler documentation:

    handle()

    This function must do all the work required to service a request.
    The default implementation does nothing. Several instance attributes
    are available to it; the request is available as self.request; the
    client address as self.client_address; and the server instance as
    self.server, in case it needs access to per-server information.

    The type of self.request is different for datagram or stream
    services. For stream services, self.request is a socket object;
    for datagram services, self.request is a pair of string and
    socket.
li-dan/typeshed,fyquah95/typeshed,tharvik/typeshed,fyquah95/typeshed,azag0/typeshed,euresti/typeshed,tharvik/typeshed