if ifModifiedSinceHeader != "" {
		if givenTime, err := amztime.ParseHeader(ifModifiedSinceHeader); err == nil {
			r.IfModifiedSince = &givenTime
		}
	}
	ifUnmodifiedSinceHeader := header.Get(xhttp.IfUnmodifiedSince)
	if ifUnmodifiedSinceHeader != "" {
		if givenTime, err := amztime.ParseHeader(ifUnmodifiedSinceHeader); err == nil {
			r.IfUnModifiedSince = &givenTime
		}
	}