ActiveHealthChecks holds configuration related to active health checks (that is, health checks which occur independently in a background goroutine).

Handler is a handler that can proxy connections.

HealthChecks configures active and passive health checks.

LoadBalancing has parameters related to load balancing.

PassiveHealthChecks holds configuration related to passive health checks (that is, health checks which occur during the normal flow of connection proxying).

Upstream represents a proxy upstream.

UpstreamPool is a collection of upstreams.