// Ideally we would use If-Unmodified-Since, but that
// particular condition seems to be ignored by Azure. Instead,
// we get the Etag before checking Mtime, and use If-Match to
// Ideally we would use If-Unmodified-Since, but that
// particular condition seems to be ignored by Azure. Instead,
// we get the Etag before checking Mtime, and use If-Match to