docs: public boolean canConvert(Class<?> fromClass, String syntax, Class<?> toClass) {
          Class<?> fixedToClass = toClass;
          if (toClass.isPrimitive()) {
              fixedToClass = primitiveTypeMap.get(toClass);
          }
          Class<?> fixedFromClass = fromClass;
          if (fromClass.isPrimitive()) {
              fixedFromClass = primitiveTypeMap.get(fromClass);
          }
          return fixedToClass.isAssignableFrom(fixedFromClass) ||
                  (converters.get(makeConverterKey(fixedFromClass, syntax, fixedToClass)) != null) ||
                  (converters.get(makeConverterKey(fixedFromClass, null, fixedToClass)) != null);
      }