code: public String apply(final JsonParser jp, CacheScope cacheScope, Supplier<String> source) throws IOException {
          return apply(CharBuffer.wrap(jp, source), cacheScope);
      }
docs: returns a String read from the JsonParser argument's current position.
  The returned value may be interned at the given cacheScope to reduce heap
  consumption
  
  @param jp
  @param cacheScope
  @return a possibly interned String
  @throws IOException