Override implementation to report all exceptions to sentry.
        log_exception() is added in Tornado v3.1.

def log_exception(self, typ, value, tb):
        """Override implementation to report all exceptions to sentry.
        log_exception() is added in Tornado v3.1.
        """
        rv = super(SentryMixin, self).log_exception(typ, value, tb)
        # Do not capture tornado.web.HTTPErrors outside the 500 range.
        if isinstance(value, WebHTTPError) and (value.status_code < 500 or value.status_code > 599):
            return rv
        self.captureException(exc_info=(typ, value, tb))
        return rv