// `cond_output` and `body_outputs`.
//
// If `status` is OK, the caller must call either TF_FinishWhile or
// TF_AbortWhile on the returned TF_WhileParams. If `status` isn't OK, the
// returned TF_WhileParams is not valid, and the caller should not call
// TF_FinishWhile() or TF_AbortWhile().
//
// Missing functionality (TODO):
// - Gradients
// - Reference-type inputs

/// Lifetime: The wrapper data structures are owned by core TensorFlow. The data
/// pointed to by the `void*` members is always owned by the plugin. The plugin
/// will provide functions to call to allocate and deallocate this data (see
/// next sections) and core TensorFlow ensures to call these at the proper time.
///
/// Plugins will never receive a `TF_*` pointer that is `nullptr`. Core
/// TensorFlow will never touch the `void*` wrapped by these structures, except