type NetworkError struct {
	Err error
}

func (n *NetworkError) Error() string {
	return n.Err.Error()
}

// Unwrap returns the error wrapped in NetworkError.
func (n *NetworkError) Unwrap() error {
	return n.Err
}

// Client - http based RPC client.
type Client struct {
	connected int32 // ref: https://golang.org/pkg/sync/atomic/#pkg-note-BUG