Data table generator for table-valued parameters

When using .AsTableValuedParameter(), is there any reason why it does not generate IL code for creating a DataTable from the object passed in? As it is currently, you have to create the DataTable in user code differently for every table type that you want to use.

I'm thinking that in the same way POCOs are being mapped to the table schema for constructing the DbCommand, they could be mapped to the table type for constructing the DataTable. With an extension method like the existing ones, the API would be:

// Given a table type KeyValueTableType with columns Key and Value
var keyValueTableParameter = new [] { 
    new KeyValueTableType { Key = "abc", Value = "qwe" },
    new KeyValueTableType { Key = "xyz", Value = "asd" }
}.AsTableValuedParameter();
// would have signature ICustomQueryParameter AsTableValuedParameter<T>(IEnumerable<T> rows)

The extension method above would (in addition to it's current implementation) be generating a dynamic method that essentially does:

var table = new DataTable();
table.Columns.Add("Key", typeof(string));
table.Columns.Add("Value", typeof(string));
foreach (var row in rows)
{
    table.Rows.Add(new[] { row.Key, row.Value });
}

Is this something that you think makes sense? Or is it too specific of a use-case, and should go into contrib?

Begin with the current .AsTableValuedParameter implementation and the existing POCO-to-table-schema mapping used when constructing DbCommand. Determine whether a generic IEnumerable overload can produce the requested DataTable for each table type; done means the proposed API and row/column mapping work without per-type user DataTable construction, with scope decided between core and contrib.