Other than patching Scylla sinks to implement new data_sink_impl::put(std::span<temporary_buffer>) overload, the PR changes transport write_response() method to stop using output_stream::write(scattered_message) because it's also gone.
Using newer seastar API, no need to backport
Closesscylladb/scylladb#26592
* github.com:scylladb/scylladb:
code: Fix indentation after previous patch
code: Switch to seastar API level 9
transport: Open-code invoke_with_counting into counting_data_sink::put
transport: Don't use scattered_message
utils: Implement memory_data_sink::put(net::packet)
ab488fbb3f