HTTP/2 and Legacy Pool APIs

FetchPHP's custom connection-pool and DNS-cache integration is deprecated since 4.1.0. withConnectionPool(), its pool diagnostics, and the handler DNS cache methods remain available for source compatibility, but they do not change request execution. FetchPHP does not borrow a pooled transport client or resolve request hosts through DnsCache.

The Connection objects hold Guzzle client instances, not established TCP or TLS sockets. They cannot guarantee socket reuse, HTTP/2 multiplexing, or connection limits. A DnsCache instance remains usable as a standalone utility; its results do not affect outgoing requests.

Reuse of HTTP connections depends on the Guzzle handler and transport. Reusing an injected Guzzle client and its handler allows that transport to manage any supported keep-alive behavior, but FetchPHP does not guarantee a socket will be reused. Do not replace request hostnames with cached IP addresses: doing so can change TLS hostname verification, SNI, proxy behavior, and routing.

HTTP/2

withHttp2() can add Guzzle version and cURL options when HTTP/2 is enabled and the cURL constants are available. It does not guarantee that a server negotiates HTTP/2. Advanced stream and window configuration values are stored as configuration and are not all translated into transport options. Guzzle's handler, cURL build, and server determine actual protocol support.

$handler = fetch_client()
    ->getHandler()
    ->withHttp2(['enabled' => true]);