JsonIgnoreCondition
When specified on DefaultIgnoreCondition,
determines when properties and fields across the type graph are ignored.
When specified on Condition, controls whether
a property or field is ignored during serialization and deserialization. This option
overrides the setting on DefaultIgnoreCondition.
Always = 1
Property is always ignored during serialization and deserialization.
Never = 0
Property is never ignored during serialization or deserialization.
If the value is the default, the property is ignored during serialization.
This is applied to both reference and value-type properties and fields.
WhenWritingNull = 3
If the value is null, the property is ignored during serialization.
This is applied only to reference-type properties and fields.