default Object getRawField(String fieldName) {
    return getField(fieldName);
  }
This same as calling getField(fieldName) except that some implementations may support
returning a PdxString instead of String.
Implementors that do not support PdxString can use use the default implementation
which simply calls getField(fieldName).

@throws PdxSerializationException if the field could not be deserialized
geode-core/src/main/java/org/apache/geode/pdx/internal/InternalPdxInstance.java