# - You can no longer insert a DOM tree, naturally. Instead, you can set up
# an XML::TemplateSAX::Buffer, let it gobble up your data, and send it
# in the way you'd insert a DOM tree. process_file_to_buffer does this
-# transparently for you, returning a buffer you can give in.
+# transparently for you, returning a buffer you can give in. (In theory,
+# one could avoid the buffering and just defer the parsing/filtering until
+# it's needed, but Expat seems non-reentrant, which means starting a parser
+# from within a begin_element callback blows up.)
#
use strict;