Clears the "static" and persistent caches.
public function flush() {
$this->fieldMap = NULL;
$this->fieldsById = array();
$this->fieldIdsByName = array();
$this->loadedAllFields = FALSE;
$this->unknownFields = array();
$this->bundleInstances = array();
$this->loadedAllInstances = FALSE;
$this->emptyBundles = array();
$this->bundleExtraFields = array();
$this->cacheBackend
->deleteTags(array(
'field_info' => TRUE,
));
}