Function mz_interchange::avro::schema::validate_schema_2

fn validate_schema_2(
    seen_avro_nodes: &mut BTreeSet<usize>,
    schema: SchemaNode<'_>
) -> Result<ScalarType>

Get the single column corresponding to a schema node. It is an error if this node should correspond to more than one column (because it is an Essential Union in the sense described in the module docs).