code: public static void setTraceStrategy(TraceStrategy traceStrategy) {
      if (TraceTrampoline.traceStrategy != null) {
        throw new IllegalStateException("traceStrategy was already set");
      }
  
      if (traceStrategy == null) {
        throw new NullPointerException("traceStrategy");
      }
  
      TraceTrampoline.traceStrategy = traceStrategy;
    }
docs: Sets the concrete strategy for creating and manipulating trace spans.
  
  <p>NB: The agent is responsible for setting the trace strategy once before any other method of
  this class is called.
  
  @param traceStrategy the concrete strategy for creating and manipulating trace spans
  @since 0.9