Brian Goetz brian.goetz at
Tue Jun 25 06:22:09 PDT 2013

> As someone said one the lambda-dev mailing list, there is no TWR in C#
> because close is called at the end of the for-each instruction.
> Why do you want user to care about releasing resources manually if this
> can be done automatically ?

Because it can't be.

What happens if:
  - no one executes a terminal op
  - a terminal op throws an exception
  - the user asks for an Iterator/Spliterator and doesn't exhaust it

This is analogous the problem with IO streams, where:

   InputStream is = ...

isn't good enough; you want try-finally (or TWR) to ensure that cleanup 

What you suggest increases the probability that the stream is closed, 
but doesn't guarantee it.  (It also is far more intrusive in the 

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