This is xnu-11215.1.10. See this file in: 
/*
 * Copyright (c) 2020, Apple Inc.  All rights reserved.
 */

 /*
 *  Interface definition for the telemetry facility.
 */

subsystem
#if	KERNEL_USER
    KernelUser
#endif	/* KERNEL_USER */
    iocompressionstats_notification 5600;

#include <mach/std_types.defs>
#include <mach/mach_types.defs>

simpleroutine	iocompressionstats_notification(
	RequestPort	iocompressionstats_port	: mach_port_t;
	in			flags			: uint32_t);