GLES READ PIXEL debug message

It’s documented that SDL_RenderReadPixels is slow, and that is certainly true, but I’ve noticed when debugging in Android that use of this function results in the following message being sent to the debug logcat stream:

D/ (23412): ++++++++++++++++ GLES READ PIXEL+++++++++++++

Outputting that message cannot be helping the speed, so what is its purpose, where is it coming from and is there some way to suppress it?