perl6 -e 'my @rand = rand xx 20; await do for ^20 { start { say "$_.."; @rand[$_].sleep; say "$_ is done" } }  '
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Unhandled exception in code scheduled on thread 4607270912Unhandled exception in code scheduled on thread 4598345728Unhandled exception in code scheduled on thread 4580495360Unhandled exception in code scheduled on thread 4616196096
Unhandled exception in code scheduled on thread 4589420544



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Unhandled exception in code scheduled on thread 4571570176
Unhandled exception in code scheduled on thread 4625121280
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Unhandled exception in code scheduled on thread 4634046464
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Unhandled exception in code scheduled on thread 4642971648
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Unhandled exception in code scheduled on thread 4651896832
Unhandled exception in code scheduled on thread 4660838400
Unhandled exception in code scheduled on thread 4669763584
Unhandled exception in code scheduled on thread 4678688768Unhandled exception in code scheduled on thread 4687613952
Unhandled exception in code scheduled on thread 4696690688

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Type check failed in binding exception; expected 'Any' but got 'Mu'
  in method break at src/gen/m-CORE.setting:18662
  in block  at src/gen/m-CORE.setting:18770
  in block  at src/gen/m-CORE.setting:18573
  in any  at /Users/ec/.rakudobrew/moar-HEAD/install/languages/perl6/runtime/CORE.setting.moarvm:1
  in block  at -e:1
  in block  at src/gen/m-CORE.setting:18769
  in block  at src/gen/m-CORE.setting:18573
  in block  at src/gen/m-CORE.setting:18506
  in block  at src/gen/m-CORE.setting:18497

Type check failed in binding exception; expected 'Any' but got 'Mu'
  in method break at src/gen/m-CORE.setting:18662
  in block  at src/gen/m-CORE.setting:18770
  in block  at src/gen/m-CORE.setting:18573
  in any  at /Users/ec/.rakudobrew/moar-HEAD/install/languages/perl6/runtime/CORE.setting.moarvm:1
  in block  at -e:1
  in block  at src/gen/m-CORE.setting:18769
  in block  at src/gen/m-CORE.setting:18573
  in block  at src/gen/m-CORE.setting:18506
  in block  at src/gen/m-CORE.setting:18497