The first extension point that is loaded in a Blocks based application. Plugins that need to start immeditatly can extend from this point, but normally it's better for them to extend from the com.blocks.BLifecycle.lifecycle extension point where they have finner control over the specific stage of application startup where the callback will be made.
In this configuration example the class method [MyController sharedInstance] will be sent early in the Blocks startup process. This configuration markup should be added to the Plugin.xml file of the plugin that declares the MyController class.
<extension point="com.blocks.Blocks.main">
<callback class="MyController sharedInstance" />
</extension>