TF_Status* status);

// Enables only graph collection in RunMetadata on the functions executed from
// this context.
TF_CAPI_EXPORT extern void TFE_ContextEnableGraphCollection(TFE_Context* ctx);

// Disables only graph collection in RunMetadata on the functions executed from
// this context.

//
// The data in the buffer will be the serialized OpList proto for ops registered
// in this address space.
TF_CAPI_EXPORT extern TF_Buffer* TF_GetAllOpList(void);

// TF_ApiDefMap encapsulates a collection of API definitions for an operation.
//
// This object maps the name of a TensorFlow operation to a description of the
// API to generate for it, as defined by the ApiDef protocol buffer (

      ContextDevicePlacementPolicy policy) = 0;
  // Returns the device placement policy for the current thread.
  virtual ContextDevicePlacementPolicy GetDevicePlacementPolicy() const = 0;

  // Configure graph collection in RunMetadata.
  virtual void SetShouldStoreGraphs(bool value) = 0;

  // Return the collected RunMetadata. This method will transfer the ownership
  // to the caller.

  virtual void MarkAsResult(Gradient* gradient) const = 0;

  // Deletes the input tensor.
  virtual void DeleteGradient(Gradient* gradient) const = 0;
};

// Traces the execution of operations, doing eager garbage collection, and
// exporting a full trace so other code can do backpropagation. Not thread-safe.
template <typename Gradient, typename BackwardFunction, typename TapeTensor>
class GradientTape {
 public: