ConsumeViewerFrame func(key string, f format.Frame)
	Flush              func()
}

// ViewerDataTraceConsumer returns a TraceConsumer that writes to w. The
// startIdx and endIdx are used for splitting large traces. They refer to
// indexes in the traceEvents output array, not the events in the trace input.
func ViewerDataTraceConsumer(w io.Writer, startIdx, endIdx int64) TraceConsumer {
	allFrames := make(map[string]format.Frame)