@NotNull
  @Override
  public BuildProgress<BuildProgressDescriptor> start(@NotNull BuildProgressDescriptor descriptor) {
    myDescriptor = descriptor;
    StartEvent event = createStartEvent(descriptor);
    myListener.onEvent(getBuildId(), event);
    return this;
  }
@NotNull
  @Override
  public BuildProgress<BuildProgressDescriptor> start(@NotNull BuildProgressDescriptor descriptor)