Slot specification

// An inventory slot
message Slot {
  // ID of the merchant for the slot (required for CreateBooking)
  string merchant_id = 1;

  // ID of the merchant service (required for CreateBooking)
  string service_id = 2;

  // Start time of the appointment slot in seconds of UTC time since Unix epoch.
  // (required for CreateBooking)
  google.protobuf.Timestamp start_time = 3;

  // Duration of the appointment slot (required for CreateBooking)
  google.protobuf.Duration duration = 4;

  // Opaque tag that identifies the availability slot and matches the value
  // provided in the availability feed (optional)
  string availability_tag = 5;

  // The set of resources that disambiguates the appointment slot, e.g. by
  // indicating the staff member and room selected by the user (optional)
  Resources resources = 6;

  reserved 7;
}