BaseStream.onClose() should take an AutoCloseable as parameter

[Remi Forax]

Currently onClose takes a Runnable so the way to transform a checked 
exception to an unchecked one
has to be done by the caller of onClose() with the risk that the 
unchecked exception will be different from
two different callers.

I strongly disagree that checked exception should be hidden that way and 
nobody care but
at least the code that transforms the checked exception to an unchecked 
one should be written once inside
the pipeline implementation and documented once in the Stream javadoc.

Rémi