OPTIONAL(name, MDStringField, ); \
OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX)); \
OPTIONAL(align, MDUnsignedField, (0, UINT64_MAX)); \
OPTIONAL(name, MDStringField, ); \
OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX)); \
OPTIONAL(align, MDUnsignedField, (0, UINT64_MAX)); \