Clickhouse sends http progress headers with the name X-ClickHouse-Progress which cannot be handled in a streaming way in akka
In the request we include our own custom header X-Internal-Identifier
so we can send the internal query id with the progress
The progress headers are being intercepted by the transport and sent to an internal source as progress events with the internal query id which will be used to route them to the query progress source
We just proxy the request/response and do not manipulate them in any way