Batch load message entities in view results

[nikanderson]

Adds a pre_render method to message_handler_field_message_render in order to batch-load Message entities rather than loading them one by one in render()

[amitaibu]

I would avoid this $messages - as we end up caching this inside message_load and here. Instead - you can do something like:

function pre_render() {

...
+    if (empty($mids)) {
        // No Message IDs.
        return;
     }
     
    // Load the Messages in a single call, so they will be statically cached in the ::render function.
     message_load_multiple($mids);
}

Then, the render function will stay as-is, the message_load will however fetch the $message from the static cache.

[amitaibu]

When would this be empty?