Same as a regular task, but the immediate prerequisites are done in parallel using Ruby threads.

Methods
Public Instance methods
invoke_prerequisites()
     # File lib/rake.rb, line 401
401:     def invoke_prerequisites
402:       threads = @prerequisites.collect { |p|
403:         Thread.new(p) { |r| Task[r].invoke }
404:       }
405:       threads.each { |t| t.join }
406:     end