bp_groups_messages_new_message( array|string $args = '' )

function bp_groups_messages_new_message( $args = '' ) {
	$send = '';
	remove_action( 'messages_message_sent', 'messages_notification_new_message', 10 );
	add_action( 'messages_message_sent', 'group_messages_notification_new_message', 10 );

	$r = bp_parse_args(
		$args,
		array(
			'sender_id'     => bp_loggedin_user_id(),
			'thread_id'     => false,   // False for a new message, thread id for a reply to a thread.
			'recipients'    => array(), // Can be an array of usernames, user_ids or mixed.
			'subject'       => false,
			'content'       => false,
			'date_sent'     => bp_core_current_time(),
			'append_thread' => false,
			'is_hidden'     => false,
			'mark_visible'  => false,
			'group_thread'  => true,
			'error_type'    => 'wp_error',
		),
		'bp_groups_messages_new_message'
	);

	// Attempt to send the message.
	$send = messages_new_message( $r );
	remove_action( 'messages_message_sent', 'group_messages_notification_new_message', 10 );
	add_action( 'messages_message_sent', 'messages_notification_new_message', 10 );

	return $send;
}