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

Methods
I
Instance Private methods
invoke_prerequisites(args, invocation_chain)

Source: show | on GitHub 

# File ../ruby/lib/rake/multi_task.rb, line 8
def invoke_prerequisites(args, invocation_chain)
  threads = @prerequisites.collect { |p|
    Thread.new(p) { |r| application[r, @scope].invoke_with_call_chain(args, invocation_chain) }
  }
  threads.each { |t| t.join }
end