EntityTagVersion  
    This version checks the etag value and pass it through conditions supplied by the remote client. Depending on the conditions, it produces the return value of enum type VersionCheckResult.
It never handles If-None-Match: *  as it is related to non-etag logic (for example, Last modified checks).
Return
VersionCheckResult.OK if all headers pass or there was no related headers, VersionCheckResult.NOT_MODIFIED for successful If-None-Match, VersionCheckResult.PRECONDITION_FAILED for failed If-Match
Parameters
- entity tag, for example file's content hash 
- whether strong or weak validation should be applied 
Properties
Functions
Appends relevant headers to the builder.
Checks requestHeaders against this version and returns VersionCheckResult.
Checks whether two entity-tags match (strong).
Specifies If-Match logic using the match function.
Specifies If-None-Match logic.