* TraceSegment} means the segment, which exists in current {@link Thread}. And the distributed trace is formed by multi
* {@link TraceSegment}s, because the distributed trace crosses multi-processes, multi-threads.
* <p>
* {@link TraceSegment} is a segment or fragment of the distributed trace. {@see https://github.com/opentracing/specification/blob/master/specification.md#the-opentracing-data-model}
* A {@link TraceSegment} means the segment, which exists in current {@link Thread}. And the distributed trace is formed
* by multi {@link TraceSegment}s, because the distributed trace crosses multi-processes, multi-threads. <p>