type BuildOptions struct {
	// ServerConfig contains the configuration that controls how the transport
	// interacts with the xDS server. This includes the server URI and the
	// credentials to use to connect to the server, among other things.
	ServerConfig *bootstrap.ServerConfig
}

type Builder interface {
	// Build creates a new xDS transport with the provided options.
	Build(opts BuildOptions) (Transport, error)
}

type StreamingCall interface {
	// Send sends the provided message on the stream.
	Send(any) error

	// Recv block until the next message is received on the stream.
	Recv() (any, error)
}

type Transport interface {
	// CreateStreamingCall creates a new streaming call to the xDS server for the
	// specified method name. The returned StreamingCall interface can be used to
	// send and receive messages on the stream.
	CreateStreamingCall(context.Context, string) (StreamingCall, error)

	// Close closes the underlying connection and cleans up any resources used by the
	// Transport.
	Close() error
}