wp_should_output_buffer_template_for_enhancement

By default, an output buffer is only started if a {@see 'wp_template_enhancement_output_buffer'} filter has been added or if a plugin has added a {@see 'wp_finalized_template_enhancement_output_buffer'} action. For this default to apply, either of the hooks must be added by the time the template is included at the {@see 'wp_before_include_template'} action. This allows template responses to be streamed unless the there is code which depends on an output buffer being opened. This filter allows a site to opt in to adding such template enhancement filters later during the rendering of the template.

// rejestracja funkcji zwrotnej
add_filter( 'wp_should_output_buffer_template_for_enhancement', 'twoja_funkcja' );

function twoja_funkcja($param_1) {
	// Twój kod
}