The Template::Alloy::Stream role works similar to the PLAY role, but instead
of accumulating the data, it prints it as soon as it is available.
All directives are supported except for the CLEAR directive which is meaningless.
Most configuration items are supported - except for the TRIM directive which cannot
be used because the output is not buffered into a variable that can be trimmed.
The WRAPPER directive is still supported - but it essentially turns off STREAM as
the content must be generated before playing the WRAPPER templates.