GL_APPLE_flush_buffer_range
https://www.khronos.org/registry/OpenGL/extensions/APPLE/APPLE_flush_buffer_range.txt
GL_APPLE_flush_buffer_range

	GL_BUFFER_SERIALIZED_MODIFY_APPLE 0x8A12
	GL_BUFFER_FLUSHING_UNMAP_APPLE 0x8A13
	void glBufferParameteriAPPLE (GLenum target, GLenum pname, GLint param)
	void glFlushMappedBufferRangeAPPLE (GLenum target, GLintptr offset, GLsizeiptr size)