Error checking vs. performance

[BurdetteLamar]

Looking closely now at improving the doc for CSV::Table and CSV::Row.

It's going to be much, much easier and clearer to document errors if we do early error checking. For example, in CSV::Row.new, we could begin:

def initialize(headers, fields, header_row = false)
      headers = Array::try_convert(headers)
      unless headers
        message = "Expected argument headers to be Array-convertible, not #{headers}"
        raise ArgumentError.new(message)
      end
      fields = Array::try_convert(fields)
      unless fields
        message = "Expected argument fields to be Array-convertible, not #{fields}"
        raise ArgumentError.new(message)
      end
      ...

Would this hurt performance too much?

The alternative, as now, is getting a missing-method message involving 'each' or 'zip', which is less clear.