parquet-thrift/src/main/java/org/apache/parquet/thrift/ThriftSchemaConverter.java
public static MessageType convertWithoutProjection(StructType struct) {
    return ThriftSchemaConvertVisitor.convert(struct, FieldProjectionFilter.ALL_COLUMNS, false);
  }
public static MessageType convertWithoutProjection(StructType struct) {
    return ThriftSchemaConvertVisitor.convert(struct, FieldProjectionFilter.ALL_COLUMNS, false);
  }
struct is not required to have known structOrUnionType, which is useful
for converting a StructType from an (older) file schema to a MessageType

@param struct the thrift type descriptor
@return the struct as a Parquet message type