Missing content-length with ureq HEAD request

[pka]

buffered_range_client::test_sync::seek_end fails with ureq.

RUST_LOG=debug cargo test --no-default-features --features ureq-sync seek_end

failures:

---- buffered_range_client::test_sync::seek_end stdout ----
....
[2025-10-03T13:09:57Z DEBUG ureq::unit] response 200 to HEAD https://flatgeobuf.org/test/data/countries.fgb
[src/buffered_range_client.rs:210:13] &header_val = None
[2025-10-03T13:09:57Z DEBUG ureq::stream] dropping stream: Stream(RustlsStream)
Error: Custom { kind: Other, error: "SeekFrom::End failed - no content-length received" }

response.header("content-length") seems to return None