contentType

MIME-type the server reported for bytes (e.g. application/bil16, image/png, application/vnd.ogc.se_xml). Set when the bytes came from a fresh HTTP response; null for cache-only reads (cache stores typically don't persist the header).

Consumers that care about format dispatch (elevation decoder, primarily) should prefer this over any "requested" format string when non-null — it reflects what the server actually returned, not what we asked for, and catches the case where a service-exception XML is returned at HTTP 200.