/**
@page conc_generation Data Generation

Production nodes that also produce data are called generators. To ease 
configuration of such generators, they are designed so that they do not 
actually produce any data until specifically asked to do so. This allows 
the application to configure any property it needs before actually 
starting to generate data. Starting generation is done using @ref 
xnStartGenerating() or @ref xn::Generator::StartGenerating(). The 
application may sometimes want to stop the generation without actually 
destroying the node (for example, if it does not need this data in 
current state, but does not want to loose configuration changes, or 
wants to have the option to quickly resume generating data (instead of 
having to initialize it again). To do so, the application may call @ref 
xnStopGenerating() or @ref xn::Generator::StopGenerating. 

In addition, for easier access, OpenNI supplies two functions that 
control <i>all</i> generators in the context: @ref 
xn::Context::StartGeneratingAll() and @ref 
xn::Context::StopGeneratingAll(). 
*/