primitive booleans instead of Booleans

[pemmasanikrishna]

favor primitive types over boxed Boolean.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[ammokhov]

this seems to intentionally set false/true to the parameter that are initially set only in certain cases, otherwise null. @wbingli @PatMyron seeking ur opinions if we should generalize and always return boolean?

[wbingli]

I would suggest don't change the property type as it will cause method change and it will cause compile error.

As suggest in #341 (comment), we can provide extra helper method, such as isSnapshotRequested to simplify it.

[pemmasanikrishna]

@wbingli I have already taken care of that change and changed the references as well. And the pr got build is successful. Do yoy want me to revert the change and provide helper method ?

[wbingli]

The point is that anyone who uses this class will be broken. The java plugin can build successful doesn't mean it won't break others. Therefore, I suggest to add helper method in the class instead of change the field type.