The sleigh allows R functions to be executed in parallel using the eachElem and eachWorker methods.
The sleigh workers are started when the sleigh object is constructed. When tasks are submitted to the sleigh, using the eachWorker and eachElem methods, the workers will execute the tasks, and return the results. When the stopSleigh method is called, the workers are stopped.
Note that a given R program can create multiple sleigh objects, which will each have it's own set of workers. This could be useful if tasks have different requirements. For example, you could create a Linux sleigh and a Windows sleigh, and Windows-specific tasks only to your Windows sleigh.