Support custom subscribe annotation

[shenghaiyang]

Support custom subscribe annotation, for example:

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
@Subscribe(threadMode = ThreadMode.BACKGROUND)
public @interface MySubscribe{}

[ctlove0523]

Why you need todefine yourself annotation?

[sitepark-veltrup]

I would also find this useful. This article describes the reason quite well.

[tomridder]

is it necessary for developers? it so ... we can let developers write an self defined annotation extends @subscribe and check the necessary variables on self defined annotation @greenrobot-team