10 thread.group.remove(thread)
12 thread.add_to_group self
13 @threads << WeakRef.new(thread)
18 @threads.delete_if { |w| !w.weakref_alive? or !w.object.alive? }
25 @threads.delete_if { |w| w.object == thread }
30 @threads.map { |w| w.object }
34 @threads.delete_if { |w| !w.weakref_alive? }
35 @threads.map { |w| w.object }