[ffresty] maxIdleConnsPerHost Setting

[onelapahead]

Follow's up #153. Reading common performance problems in Go net/http, the maxConnsPerHost is helpful being unlimited by default but it sounds like the maxIdleConnsPerHost will always default to 2 based on the source:

// DefaultMaxIdleConnsPerHost is the default value of [Transport]'s
// MaxIdleConnsPerHost.
const DefaultMaxIdleConnsPerHost = 2
// ...
type Transport struct {
  // ...
  // MaxIdleConnsPerHost, if non-zero, controls the maximum idle
  // (keep-alive) connections to keep per-host. If zero,
  // DefaultMaxIdleConnsPerHost is used.
  MaxIdleConnsPerHost int
  // ...
}

Based on https://stackoverflow.com/a/31810116 and https://www.reddit.com/r/golang/comments/1730po3/comment/k51x8jn/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button we should see our clients default to creating many more connections per host under higher load.

[EnriqueL8]

Looks good - thanks for the clear explanation and links

[peterbroadhurst]

Understand and agree with this change.

Including the fact it changes default behavior for all consumers of this library.