+/**
+ * Retrieve message fragments by fragment ID range.
+ *
+ * @param h
+ * Handle for the PSYCstore.
+ * @param channel_key
+ * The channel we are interested in.
+ * @param slave_key
+ * The slave requesting the fragment. If not NULL, a membership test is
+ * performed first and the fragment is only returned if the slave has
+ * access to it.
+ * @param first_fragment_id
+ * First fragment ID to retrieve.
+ * Use 0 to get the latest message fragment.
+ * @param last_fragment_id
+ * Last consecutive fragment ID to retrieve.
+ * Use 0 to get the latest message fragment.
+ * @param fragment_cb
+ * Callback to call with the retrieved fragments.
+ * @param result_cb
+ * Callback to call with the result of the operation.
+ * @param cls
+ * Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_fragment_get (struct GNUNET_PSYCSTORE_Handle *h,
+ const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+ const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+ uint64_t first_message_id,
+ uint64_t last_message_id,
+ GNUNET_PSYCSTORE_FragmentCallback fragment_cb,
+ GNUNET_PSYCSTORE_ResultCallback result_cb,
+ void *cls);
+
+
+/**
+ * Retrieve latest message fragments.
+ *
+ * @param h
+ * Handle for the PSYCstore.
+ * @param channel_key
+ * The channel we are interested in.
+ * @param slave_key
+ * The slave requesting the fragment. If not NULL, a membership test is
+ * performed first and the fragment is only returned if the slave has
+ * access to it.
+ * @param first_fragment_id
+ * First fragment ID to retrieve.
+ * Use 0 to get the latest message fragment.
+ * @param last_fragment_id
+ * Last consecutive fragment ID to retrieve.
+ * Use 0 to get the latest message fragment.
+ * @param fragment_limit
+ * Maximum number of fragments to retrieve.
+ * @param fragment_cb
+ * Callback to call with the retrieved fragments.
+ * @param result_cb
+ * Callback to call with the result of the operation.
+ * @param cls
+ * Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */
+struct GNUNET_PSYCSTORE_OperationHandle *
+GNUNET_PSYCSTORE_fragment_get_latest (struct GNUNET_PSYCSTORE_Handle *h,
+ const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
+ const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
+ uint64_t fragment_limit,
+ GNUNET_PSYCSTORE_FragmentCallback fragment_cb,
+ GNUNET_PSYCSTORE_ResultCallback result_cb,
+ void *cls);
+
+
+/**
+ * Retrieve all fragments of messages in a message ID range.
+ *
+ * @param h
+ * Handle for the PSYCstore.
+ * @param channel_key
+ * The channel we are interested in.
+ * @param slave_key
+ * The slave requesting the message.
+ * If not NULL, a membership test is performed first
+ * and the message is only returned if the slave has access to it.
+ * @param first_message_id
+ * First message ID to retrieve.
+ * @param last_message_id
+ * Last consecutive message ID to retrieve.
+ * @param fragment_limit
+ * Maximum number of fragments to retrieve.
+ * @param method_prefix
+ * Retrieve only messages with a matching method prefix.
+ * @param fragment_cb
+ * Callback to call with the retrieved fragments.
+ * @param result_cb
+ * Callback to call with the result of the operation.
+ * @param cls
+ * Closure for the callbacks.
+ *
+ * @return Handle that can be used to cancel the operation.
+ */