private FieldMarkupFunction<T> createCommentMarkupFunc(Method commentGetter,
			CommentType commentType, String sep) {
		return (context, session) -> {
			T obj = context.getStructureInstance();
			Object val = ReflectionHelper.callGetter(commentGetter, obj);
			if (val != null) {
				if (val instanceof Collection<?> c && c.isEmpty()) {
					return;
				}
				session.appendComment(context, commentType, null, val.toString(), sep);
			}
		};
	}
Creates a FieldMappingInfo instance, used when the structure is variable length and there is
no pre-defined Ghidra Structure data type.

@param <T> structure mapped class type
@param field java field
@param fieldName name of Ghidra structure field
@param signedness {@link Signedness} enum
@param length override of structure field, or -1
@return new {@link FieldMappingInfo} instance
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/golang/structmapping/FieldMappingInfo.java