id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
22239	wp_ob_end_flush_all() tries to destroy non-destroyable output buffers	dd32		"`wp_ob_end_flush_all()` currently tries to flush & destroy every PHP Output buffer that is enabled on the current installation.
However, not every type of PHP Output buffer can be destroyed, which will cause a PHP Notice when attempts to do so are made.
An example of this is PHP extensions such as New Relic, or PHP output buffers created with the `$erase` flag set to false in `ob_start()`

An example is when New Relic is installed on a host, also [https://newrelic.com/docs/php/php-agent-faq#rum-obclean see New Relics FAQ entry] on the issue.
{{{
( ! ) Notice: ob_end_flush(): failed to send buffer of New Relic auto-RUM (1) in ../trunk/wp-includes/functions.php on line 2641
Call Stack
#	Time	Memory	Function	Location
1	0.8510	4328360	shutdown_action_hook( )	../load.php:0
2	0.8510	4328440	do_action( )	../load.php:556
3	0.8510	4329856	call_user_func_array ( )	../plugin.php:406
4	0.8510	4329888	wp_ob_end_flush_all( )	../plugin.php:406
5	0.8511	4330064	ob_end_flush ( )	../functions.php:2641
}}}

Somewhat similar to #18239
I'm not sure of what the ideal solution for this would be for !WordPress, but wanted to record the issue being known."	defect (bug)	new	normal	Awaiting Review	Warnings/Notices		normal