API and spec review for Stream

[Brian Goetz]

I have posted a survey at:
   https://www.surveymonkey.com/s/59CTHS8

This is a hopefully-final review of the API and preliminary review of 
the specification for the single class Stream.  Docs are linked from the 
survey.  Usual password.  Any and all constructive comments welcome.

It is known that the specs are incomplete; what is here is a start. 
Suggestions for improvement are welcome.