[VK API] Как сделать отправку больших сообщений?

$params = array(
    'user_id'       => $uid,
    'message'       => $long_message,
    'random_id'     => rand(1E9, 9E9)
    'access_token'  => $token,
    'v'             => 5.64,
);

$ch = curl_init( 'https://api.vk.com/method/messages.send');

curl_setopt_array( $ch, array(
    CURLOPT_POST            => TRUE,
    CURLOPT_POSTFIELDS      => $params,

    CURLOPT_RETURNTRANSFER  => TRUE,
    CURLOPT_SSL_VERIFYPEER  => FALSE,
    CURLOPT_SSL_VERIFYHOST  => FALSE,
    CURLOPT_CONNECTTIMEOUT  => 10,
    CURLOPT_TIMEOUT         => 10,
));

$result = curl_exec( $ch);

$data = json_decode( $result);

$message_id = $data['response'];