@Target(value={FIELD,PARAMETER,METHOD})
@Retention(value=RUNTIME)
public @interface Hdfs
Each extension module needs to properly bind whatever it will use, but sometimes different modules need to bind the
same class which will lead to the duplicate injection error. To avoid this problem, each module is supposed to bind
different instances. This is a binding annotation for druid-hdfs-storage extension. Any binding for the same type
should be distinguished by using this annotation.