This fixes the mount read throughput issue where HTTP GET requests to the
same volume server were being serialized even with high -concurrentReaders.
The issue was that:
1. HTTP/2 multiplexes all requests over a single TCP connection
2. Even with HTTP/1.1, ForceAttemptHTTP2 defaults to true in Go
Changes:
- Set ForceAttemptHTTP2: false on http.Transport to disable HTTP/2
- Set MaxConnsPerHost: 0 (unlimited) to allow parallel connections per host
- For HTTPS, set NextProtos to only 'http/1.1' to prevent HTTP/2 negotiation
This allows multiple goroutines to use separate TCP connections to the same
volume server, enabling true parallel chunk fetching and better network
bandwidth utilization.
Relates to: #7504