Optionalbatch_Subtrees buffered per crossing (default 1: each subtree is delivered as
soon as it reduces, and a false return stops the parse with minimal
run-ahead — raise it to amortize crossings on dense streams).
OptionalbatchAlias of batch_size.
REQUIRED: the rule display name(s) whose completed subtrees are streamed.
Options for the public
parseStream(text, onSubtree, opts).