Discussed with Mike the fact that there's some functionality within the DFDL code base that should be refactored:

DFDLDelimParser needs to have the regular expression generating aspect refactored out of it so that we don't have to perform this operation every time parse is called.

Separate StringDelimitedEndOfData into a Static and Dynamic versions so that we can reduce the expense of generating the regular expressions for the delimiters every time this primitive is called. A Static version should only have to generate the regular expressions once whereas the Dynamic version will have to generate it every time.