att_write_callback_t

ATT Client Write Callback for Dynamic Data Each Prepared Write Request triggers a callback with transaction mode ATT_TRANSACTION_MODE_ACTIVE. On Execute Write, the callback will be called with ATT_TRANSACTION_MODE_VALIDATE and allows to validate all queued writes and return an application error. If none of the registered callbacks return an error for ATT_TRANSACTION_MODE_VALIDATE and the callback will be called with ATT_TRANSACTION_MODE_EXECUTE. Otherwise, all callbacks will be called with ATT_TRANSACTION_MODE_CANCEL. If the additional validation step is not needed, just return 0 for all callbacks with transaction mode ATT_TRANSACTION_MODE_VALIDATE.