code: public static void annotateOnHttpResponseBuffer(String key)	{
          TracyThreadContext ctx = threadContext.get();
          if (isValidContext(ctx)) {
              ctx.annotateOnHttpResponseBuffer(key);
          }
      }
docs: This method is used to capture annotations which should be sent back to the HTTP client
  HttpResponse annotations are created by this method and retrieved using {@link #getHttpResponseBufferAnnotations}
  when the HTTP response header is to be returned as shown in example below<br>
  <code><pre>
  ...
  Tracy.annotate("key1", "val1");
  annotateOnHttpResponseBuffer("key1");
  </pre></code>
  annotateOnHttpResponseBuffer(key) must be called after a (Tracy frame) Tracy.annotation(key, value) as it will
  retrieve the value from the recently created Tracy.annotation.<br>
  annotateOnHttpResponseBuffer(key) can be called from any point in the Tracy frame stack. Tracy will store them
  at the topmost level of the thread context to be easily accessible using {@link #getHttpResponseBufferAnnotations} method
  
  @param key defines the recently used key used in Tracy.annotate(key, val) which is to be sent back in the HTTP response header