Is your feature request related to a problem?

When doing a bulk copy, if a column mapping that has an invalid destination column name is specified, an exception is thrown. Specifically InvalidOperationException with the message The given ColumnMapping does not match up with any column in the source or destination. For tables that have a lot of columns it is really hard to zero in on the mismatching column.

You can repro this behavior by referencing the test case MissingTargetColumnTest under SqlBulkCopyTest

Describe the solution you'd like

It would be nice if the exception message gave a hint on which column had an issue. The exception message could include the name of first mismatched column name.