[rustls::ServerConfig] provider backed by an async stream.

This module exposes a [ServerConfigProvider] that holds the "current" TLS server configuration and updates it whenever a new config arrives from a user-supplied stream (see [ServerConfigStreamBuilder]).

The background task performs exponential backoff (10ms -> 10s, doubling) when the stream fails, and attempts to re-create the stream via the builder. Call [ServerConfigProvider::get_config] whenever you need an [Arc<ServerConfig>].

Overview

• Implement [ServerConfigStreamBuilder] to produce a stream of fresh ServerConfig instances (e.g., reading from disk, a secret store, or watching a certificate manager).
• Start the provider with [ServerConfigProvider::start].
• Use [ServerConfigProvider::get_config] wherever you need the current config (e.g., inside an acceptor loop).
• Optionally monitor liveness via [ServerConfigProvider::stream_healthy].

Tracing

If the tracing feature is enabled, the provider will emit diagnostics (debug/info/error) about updates and reconnection attempts.