eglSetDamageRegionKHR not work because eglCreatePbufferSurface then glFlush BUT no eglSwapBuffersWithDamageKHR

OpenGL OpenGL: Advanced Coding
1

eglSetDamageRegionKHR not work because eglCreatePbufferSurface then glFlush BUT no eglSwapBuffersWithDamageKHR.
how to resolve? Thanks!