What is purpose of iterate in convertToValue?

Whether you want to process the input all at one time.

false : Processes all input data at one time. This is the default.

true : Processes top level records (children of the document root) in the flat file schema one at a time. After all child records of the top level record are processed, the iterator moves to the top level of the next record in the flat file schema, until all records are processed =