Function paho_mqtt_sys::MQTTAsync_setBeforePersistenceWrite

pub unsafe extern "C" fn MQTTAsync_setBeforePersistenceWrite(
    handle: MQTTAsync, 
    context: *mut c_void, 
    co: MQTTPersistence_beforeWrite
) -> c_int

Sets the MQTTPersistence_beforeWrite() callback function for a client. @param handle A valid client handle from a successful call to MQTTAsync_create(). @param context A pointer to any application-specific context. The the context pointer is passed to the callback function to provide access to the context information in the callback. @param co A pointer to an MQTTPersistence_beforeWrite() callback function. NULL removes the callback setting.