According my company already had the ID generation algorithm to generate the trace Id, which it was in used. And I find the skywalking，the trace Id was default generation , and I can't extend it. Also I find the `ContextManagerExtendService` can do some thing before the traceContext created . But the only way I can do was extend the `TraceIgnoreExtendService` and Override the `createTraceContext` method. I think the better way was the skywalking create a default `TraceContext` to let user how to modify it. just like what I confuse in this code
https://github.com/apache/skywalking/commit/e0b7306e5ddae91adc0faf09f505dee9401ded01 After all I am not good at English. hope some people know what I say.
