code: @Nonnull
    public void setInvoker (@Nonnull final IAjaxInvoker aInvoker)
    {
      ValueEnforcer.notNull (aInvoker, "Invoker");
      m_aRWLock.writeLocked ( () -> m_aInvoker = aInvoker);
    }
docs: Set the global invoker to be used. This can be changed during the runtime
  of the application and is independent of the registry state. Use this to
  e.g. increase the debug logging or tracing of the invocations.
  
  @param aInvoker
  The invoker to be used. May not be <code>null</code>.