RFR 8169808 Stream returning methods should specify if they are late binding

[Doug Lea]

On 11/22/2016 08:33 PM, Martin Buchholz wrote:
> PriorityBlockingQueue has a late-binding-style, snapshot spliterator
> that does not report IMMUTABLE.  It *is* immutable ... after the first
> access!  Should we add IMMUTABLE?

Probably not.
This might overly constrain future improvements; for example, someday
replacing with some linked structure.
Arguably, if so, we could just change the reported characteristics,
but that could be surprising to users, and possibly lead to subtle user 
bugs.

-Doug