void * libssh2_session_callback_set(LIBSSH2_SESSION *session, int cbtype, void *callback);
cbtype - Callback type. One of the types listed in Callback Types.
callback - Pointer to custom callback function. The prototype for this function must match the associated callback declaration macro.
Sets a custom callback handler for a previously initialized session object. Callbacks are triggered by the receipt of special packets at the Transport layer. To disable a callback, set it to NULL.