Suggestion for improving error messaging for marc rake file

[brittnylapierre]

Hello! I am writing to suggest an enhancement to the error messaging of the marc indexer rake file.

It could be pertinent to know which record(s) produce an error especially for large files with thousands of records.

If a single record in a marc file has a formatting issue, this is what will be printed:
rake aborted! INFO Traject: Indexer with 1 processing threads, reader: Traject::MarcReader and writer: Traject::SolrJsonWriter NoMethodError: undefined method pack for nil:NilClass /usr/local/bundle/gems/marc-1.2.0/lib/marc/reader.rb:362:in block in decode ...

I believe that printing the '001' field along with the message that the record is not formatted correctly would be more helpful, for example,
rake aborted! INFO: Record <value of 001 field> has a formatting issue and could not be processed. Please remove the record from your file, or correct any issues, and try again.