@Nullable
    public static TraceContext get() {
        return THREAD_LOCAL_CONTEXT.get();
    }
Internal class for manipulate the internal {@link ThreadLocal} for {@link RequestContextCurrentTraceContext}.
This class is reserved for internal usage and is subject to behavior change any time.
brave/brave6/src/main/java/com/linecorp/armeria/internal/common/brave/InternalTraceContextUtil.java