When calling the BulkMerge and BulkInsert, there are instances that the users would like to return the generated identity values right after the actual operations.

This story will enable the user to set the flag (aka: argument) to return the data entity identity values.

Consider the following calls.

For Merge:

var customers = GetCustomers(10);
connection.BulkMerge<Customer>(customers, isReturnIdentity: true);

For Insert:

var customers = GetCustomers(10);
connection.BulkInsert<Customer>(customers, isReturnIdentity: true);

Special case for BulkInsert. If the isReturnIdentity argument is false, then do not create a pseudo-temporary table.