Issue #15: rxros::spin() funtion uses unnecessary many threads

Author: henrik7264

README.md

@@ -163,13 +163,18 @@ The other purpose of the rxros::spin function is to dispatch messages from ROS t
 Failure to omit the rxros::spin function will cause the program to terminate immediately and observables based on ROS topics
 will not emit any events.
 
+rxros::spin will per default use one thread for dispatching messages. For most nodes this will be sufficient.
+In special cases where a node uses many topics it may be necessary to use more threads for dispatching messages.
+This can be achieved by specifying the number of threads the rxros::spin function should use.
+A special case is rxros::spin(0) which will allocate a thread for each CPU core.
+ 
 The Example below shows a minimal RxROS program that creates a ROS node named “my_node”.
 The program will due to rxros:spin() continue to run until it is either shutdown or terminated.
 
 ### Syntax
 
 ```cpp
-void rxros::spin();
+void rxros::spin(uint32_t thread_count = 1);
 ```
 
 ### Example

rxros/include/rxros/rxros.h

@@ -48,8 +48,8 @@ namespace rxros
         ros::init(argc, argv, name);
     }
 
-    static void spin() {
-        ros::MultiThreadedSpinner spinner(0); // Use a spinner for each available CPU core
+    static void spin(uint32_t thread_count = 1) { // Use per default 1 thread for spinning
+        ros::MultiThreadedSpinner spinner(thread_count);
         spinner.spin();
     }