indicate the number of fields this RecordParser is expecting on each line.
return the number of fields in this line. All records will have this number of fields. This is used for discovery and to configure the parser.
return the next record in a String, or null of no more records exist.
attempts to extract fields from the record, returning true if the record could be split.
returns true if the line appears to be a record. If it is a record, then the record is inserted into the builder.