Act on a field instance being created.
This hook lets modules react to the creation of a field instance. It is called after the definition is saved, so it cannot be used to modify the instance itself.
$instance: The instance just created.
Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.
function hook_field_create_instance($instance) {
// @todo Needs function body.
}