attachReportingTrackers (summary, emitter) {
        var cache = {},
            executions = summary.run.executions;

        emitter.on('beforeItem', function (err, o) {
            if (err || !_.get(o, 'cursor.ref')) { return; }

            cache[o.cursor.ref] = _.assignIn(cache[o.cursor.ref] || {}, {
                cursor: o.cursor,
                item: o.item
            });
        });

        // save all responses in executions array
        emitter.on('request', function (err, o) {
            if (!_.get(o, 'cursor.ref')) { return; }

            var execution = cache[o.cursor.ref] = (cache[o.cursor.ref] || {});

            executions.push(_.assignIn(execution, {
                cursor: o.cursor,
                request: o.request,
                response: o.response,
                id: _.get(o, 'item.id')
            }, err && {
                requestError: err || undefined
            }));
        });

        // save all script execution errors in each execution
        emitter.on('script', function (err, o) {
            if (!_.get(o, 'cursor.ref')) { return; }

            var execution = cache[o.cursor.ref] = (cache[o.cursor.ref] || {}),
                eventName = o && o.event && (o.event.listen + 'Script');

            // store the script error corresponding to the script event name
            err && (execution && eventName) && (execution[eventName] || (execution[eventName] = [])).push({
                error: err
            });
        });

        // save all assertions in each execution
        emitter.on('assertion', function (err, o) {
            if (!_.get(o, 'cursor.ref')) { return; }

            var execution = cache[o.cursor.ref] = (cache[o.cursor.ref] || {});

            if (!execution) { return; }

            (execution.assertions || (execution.assertions = [])).push({
                assertion: o.assertion,
                skipped: o.skipped,
                error: err || undefined
            });
        });
    }
This stores any fatal error during the run that caused the run to abort prematurely.

@type {Error}