SpringCloud 连续跨度

有时，您不想创建一个新跨度，但想继续一个跨度。这种情况的示例如下：

要继续跨度，可以使用brave.Tracer，如以下示例所示：

// let's assume that we're in a thread Y and we've received
// the `initialSpan` from thread X
Span continuedSpan = this.tracer.toSpan(newSpan.context());
try {
	// ...
	// You can tag a span
	continuedSpan.tag("taxValue", taxValue);
	// ...
	// You can log an event on a span
	continuedSpan.annotate("taxCalculated");
}
finally {
	// Once done remember to flush the span. That means that
	// it will get reported but the span itself is not yet finished
	continuedSpan.flush();
}