Change when Paid Memberships Pro starts and stops PHP sessions.

my_change_pmpro_sessions_start_and_stop.php

<?php
/**
 * Change when Paid Memberships Pro starts and stops PHP sessions.
 * Add this code below to your PMPro Customizations Plugin - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_change_pmpro_sessions_start_and_stop() {
	// make sure PMPro has loaded
	if( !function_exists( 'pmpro_start_session' ) ) {
		return;
	}
	
	// start sessions ASAP
	remove_action( 'pmpro_checkout_preheader', 'pmpro_start_session', -1 );
	pmpro_start_session();
	
	// removing this will cause PHP to close the session when all scripts end
	remove_action( 'pmpro_after_checkout', 'pmpro_close_session', 32768 );
	
}
add_action('plugins_loaded', 'my_change_pmpro_sessions_start_and_stop');