src/Zf2Forum/Model/Message/Message.php
public function setTimestampCreated($postTime)
    {
        if ($postTime instanceof DateTime) {
            $this->timestampCreated = $postTime;
        } else {
            $this->timestampCreated = new DateTime($postTime);
        }
        return $this;
    }
public function setTimestampCreated($postTime)
    {
        if ($postTime instanceof DateTime) {
            $this->timestampCreated = $postTime;
        } else {
            $this->timestampCreated = new DateTime($postTime);
        }
        return $this;
    }
Set postTime.

@param mixed $postTime the value to be set