messages edit method fails as custom data is sent as array not an object

[fabregas4]

Firstly, the edit() method should not require $custom to be passed in. This should be optional.

Secondly the method does not work. The API rejects the request as it is expecting an object not an array. It returns Bad request. Content: {"reasons":{"custom":"Expected object but got array"}

Need to put (object) in front of $custom, like so:
$this->httpPut("conversations/$conversationId/messages/$messageId", ['text' => $text, 'custom' => (object) $custom])