Use with serde_as to control serde for human-readable serialization and
deserialization H : serde_as SerializeAs/DeserializeAs delegation for
human readable in/output R : serde_as SerializeAs/DeserializeAs delegation
for non-human readable in/output
A marker for type tags that are serialized as strings. Normally, a
type tag is serialized as a string for readable formats, and as a byte array
for non-readable formats. This marker can be used to serialize a type tag as
a string even in non-readable formats.