public static void enableCategories ( Category ... categories ) throws IOException { if ( s_tracer == null ) { start ( ) ; } final VoltTrace tracer = s_tracer ; assert tracer != null ; final ImmutableSet . Builder < Category > builder = ImmutableSet . builder ( ) ; builder . addAll ( tracer . m_enabledCategories ) ; builder . addAll ( Arrays . asList ( categories ) ) ; tracer . m_enabledCategories = builder . build ( ) ; }
Enable the given categories . If the tracer is not running at the moment create a new one .