Format a throughput value (bytes/s) into a human-readable string using
decimal units (MB/s = 10^6 B/s, the network-convention) — bandwidth is
almost universally reported in decimal, even when storage uses binary.
Create an in-memory TLS session store suitable for sharing across multiple
requests (e.g. across a benchmark -n loop). Pass the returned Arc into
HttpRequest::tls_session_store on every request that should be able to
resume a previous TLS session.