+ * If MESHLINK_CHANNEL_NO_PARTIAL is set, then the result will either be len,
+ * 0 if the buffer is currently too full, or -1 if len is too big even for an empty buffer.
+ */
+extern ssize_t meshlink_channel_send(struct meshlink_handle *mesh, struct meshlink_channel *channel, const void *data, size_t len);
+
+/// A callback for cleaning up buffers submitted for asynchronous I/O.
+/** This callbacks signals that MeshLink has finished using this buffer.
+ * The ownership of the buffer is now back into the application's hands.
+ *
+ * @param mesh A handle which represents an instance of MeshLink.
+ * @param channel A handle for the channel which used this buffer.
+ * @param data A pointer to a buffer containing the enqueued data.
+ * @param len The length of the buffer.
+ * @param priv A private pointer which was set by the application when submitting the buffer.
+ */
+typedef void (*meshlink_aio_cb_t)(struct meshlink_handle *mesh, struct meshlink_channel *channel, const void *data, size_t len, void *priv);
+
+/// A callback for asynchronous I/O to and from filedescriptors.
+/** This callbacks signals that MeshLink has finished using this filedescriptor.
+ *
+ * @param mesh A handle which represents an instance of MeshLink.
+ * @param channel A handle for the channel which used this filedescriptor.
+ * @param fd The filedescriptor that was used.
+ * @param len The length of the data that was successfully sent or received.
+ * @param priv A private pointer which was set by the application when submitting the buffer.
+ */
+typedef void (*meshlink_aio_fd_cb_t)(struct meshlink_handle *mesh, struct meshlink_channel *channel, int fd, size_t len, void *priv);
+
+/// Transmit data on a channel asynchronously
+/** This registers a buffer that will be used to send data to the remote node.
+ * Multiple buffers can be registered, in which case data will be sent in the order the buffers were registered.
+ * While there are still buffers with unsent data, the poll callback will not be called.
+ *
+ * \memberof meshlink_channel
+ * @param mesh A handle which represents an instance of MeshLink.
+ * @param channel A handle for the channel.
+ * @param data A pointer to a buffer containing data sent by the source, or NULL if there is no data to send.
+ * After meshlink_channel_aio_send() returns, the buffer may not be modified or freed by the application
+ * until the callback routine is called.
+ * @param len The length of the data, or 0 if there is no data to send.
+ * @param cb A pointer to the function which will be called when MeshLink has finished using the buffer.
+ * @param priv A private pointer which is passed unchanged to the callback.
+ *
+ * @return True if the buffer was enqueued, false otherwise.
+ */
+extern bool meshlink_channel_aio_send(struct meshlink_handle *mesh, struct meshlink_channel *channel, const void *data, size_t len, meshlink_aio_cb_t cb, void *priv);
+
+/// Transmit data on a channel asynchronously from a filedescriptor
+/** This will read up to the specified length number of bytes from the given filedescriptor, and send it over the channel.
+ * The callback may be returned early if there is an error reading from the filedescriptor.
+ * While there is still with unsent data, the poll callback will not be called.
+ *
+ * \memberof meshlink_channel
+ * @param mesh A handle which represents an instance of MeshLink.
+ * @param channel A handle for the channel.
+ * @param fd A file descriptor from which data will be read.
+ * @param len The length of the data, or 0 if there is no data to send.
+ * @param cb A pointer to the function which will be called when MeshLink has finished using the filedescriptor.
+ * @param priv A private pointer which is passed unchanged to the callback.
+ *
+ * @return True if the buffer was enqueued, false otherwise.