+ * @brief get the number of transforms in current proposal.
+ *
+ * @param this calling proposal_substructure_t object
+ * @return transform count in current proposal
+ */
+ size_t (*get_transform_count) (proposal_substructure_t *this);
+
+ /**
+ * @brief get size of the set spi in bytes.
+ *
+ * @param this calling proposal_substructure_t object
+ * @return size of the spi in bytes
+ */
+ size_t (*get_spi_size) (proposal_substructure_t *this);
+
+ /**