G-suite with TLS for SMF, using AUTH LOGIN with passed username and password (partial file)

Subs-Post.php

// Main partion of code, enabling SMF 2.0.15 via SMTP with TLS to work successfully.
// Remember this only works when using username and password via the SMTP services from G-suite.
// This if-clause and partions of the code is found within the function smtp_mail()
	if ($modSettings['mail_type'] == 1 && $modSettings['smtp_username'] != '' && $modSettings['smtp_password'] != '')
	{
		// Determine the hostname we want to send with each Extended hello and hello.
		if (function_exists('gethostname') && gethostname() !== false)
			$helo = gethostname(); 	// Server hostname
		elseif (function_exists('php_uname'))
			$helo = php_uname('n');	// Server hostname
		elseif (array_key_exists('SERVER_NAME',$_SERVER) && !empty($_SERVER['SERVER_NAME']))
			$helo = $_SERVER['SERVER_NAME'];	// Web server hostname

		if (empty($helo))
			$helo = $webmaster_email;
		
		// EHLO could be understood to mean encrypted hello...
		if (server_parse('EHLO ' . $helo, $socket, null) == '250') {

			// Send STARTTLS to enable encryption
			if (!server_parse('STARTTLS', $socket, '220'))
				return false;
			// Enable the encryption
			// php 5.6+ fix
			$crypto_method = STREAM_CRYPTO_METHOD_TLS_CLIENT;
			if (defined('STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT'))
			{
				$crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT;
				$crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT;
			}
			if (!@stream_socket_enable_crypto($socket, true, $crypto_method))
				return false;
			// Send the EHLO command again
			if (!server_parse('EHLO ' . $helo, $socket, null) == '250')
				return false;

			if (!server_parse('AUTH LOGIN', $socket, '334'))
				return false;
			// Send the username and password, encoded.
			if (!server_parse(base64_encode($modSettings['smtp_username']), $socket, '334'))
				return false;
			// The password is already encoded ;)
			if (!server_parse($modSettings['smtp_password'], $socket, '235'))
				return false;
		}
		elseif (!server_parse('HELO ' . $modSettings['smtp_host'], $socket, '250'))
			return false;
	}
	else
	{
		// Just say "helo".
		if (!server_parse('HELO ' . $modSettings['smtp_host'], $socket, '250'))
			return false;
	}