namespace {
using Signature = DeviceCompilationClusterSignature;
using TensorTypeAndShape = Signature::TensorTypeAndShape;

// Functor that converts a Signature's arg to a human readable string.
struct SignatureHumanStringAppender {
  explicit SignatureHumanStringAppender(std::string* dest) : dest(dest) {}
  std::string* dest;
  void operator()(const Tensor& arg) {
    absl::StrAppend(dest, "; ", arg.DebugString());
  }