'Begin sending whitespace periodically to keep the connection alive.
May be disabled by setting::
self.whitespace_keepalive = False
The keepalive interval can be set using::
self.whitespace_keepalive_interval = 300'

def _start_keepalive(self, event):

    if self.whitespace_keepalive:
        self.schedule(u'Whitespace    Keepalive', self.whitespace_keepalive_interval, self.send_raw, args=(u'    ',), kwargs={u'now': True}, repeat=True)
