markMessageRead() public method

Mark a message in a Google Voice Inbox or Voicemail as read.
public markMessageRead ( $message_id )
$message_id The id of the message to update.
// NOTE: Full email address required.
$gv = new GoogleVoice('*****@*****.**', 'password');
// Call a phone from one of your forwarding phones.
$gv->callNumber('9995551212', '5558675309', 'mobile');
// Cancel in-progress call placed using callNumber.
$gv->cancelCall('9995551212', '5558675309', 'mobile');
// Send an SMS to a phone number.
$gv->sendSMS('9995551212', 'Sending a message!');
// Get all unread SMSs from your Google Voice Inbox.
$sms = $gv->getUnreadSMS();
$msgIDs = array();
foreach ($sms as $s) {
    echo 'Message from: ' . $s->phoneNumber . ' on ' . $s->displayStartDateTime . ': ' . $s->messageText . "<br><br>\n";
    if (!in_array($s->id, $msgIDs)) {
        // Mark the message as read in your Google Voice Inbox.
        $gv->markMessageRead($s->id);
        $msgIDs[] = $s->id;
    }
}
// Get all unread messages from your Google Voice Voicemail.
$voice_mails = $gv->getUnreadVoicemail();
$msgIDs = array();
foreach ($voice_mails as $v) {
    echo 'Message from: ' . $v->phoneNumber . ' on ' . $v->displayStartDateTime . ': ' . $v->messageText . "<br><br>\n";
    if (!in_array($v->id, $msgIDs)) {
        // Mark the message as read in your Google Voice Voicemail.
        $gv->markMessageRead($v->id);
        $msgIDs[] = $v->id;
    }
}
// Download all unread Google Voice voicemails as indididual MP3 files.