Deserializing record structs doesn't respect default arguments.

[whatston3]

Produced on 275.2.0.

Reproduction

In DataRecordTest.cs, add the following definitions:

    [DataRecord]
    public partial record struct OneByteOneDefaultIntRecordStruct(byte A, int B = 5);

    [Test]
    public void OneByteOneDefaultIntRecordStructTest()
    {
        var mapping = new MappingDataNode {{"a", "1"}};
        var val = Serialization.Read<OneByteOneDefaultIntRecordStruct>(mapping);

        Assert.Multiple(() =>
        {
            Assert.That(val.A, Is.EqualTo(1));
            Assert.That(val.B, Is.EqualTo(5));
        });
    }

Run the tests. OneByteOneDefaultIntRecordStructTest will fail, as val.B has a value of 0.