Update Headers. with ETag(String eTag) 方法
Set the ETag HTTP response header. This is an opaque string. You can use it to detect whether the resource has changed between requests. In particular, you can pass the ETag to one of the If-Modified-Since, If-Unmodified-Since, If-Match or If-None-Match headers.
public TaskUpdateHeaders withETag(String eTag)
the eTag value to set
the TaskUpdateHeaders object itself.