Microsoft.Extensions.DependencyInjection registration extensions for
RustPlusApi.Fcm.
// one configured listener (singleton, container-disposed)
services.AddRustPlusFcm(credentials);
// runtime credentials (e.g. from FcmRegistration): caller-owned listeners via the factory
services.AddRustPlusFcmFactory();
await using var fcm = provider.GetRequiredService<IRustPlusFcmFactory>().Create(credentials);Logging auto-wires from the host's ILoggerFactory; tuning via IOptions<RustPlusFcmSocketOptions>.
FCM listeners are single-connection — create a new one to reconnect.