Public Overloads Function AddRange( _
   ByVal unorderedItems As IEnumerable(Of KeyValuePair(Of TKey,TValue)), _
   ByVal allowUpdates As Boolean _
) As Integer

public int AddRange( 
   IEnumerable<KeyValuePair<TKey,TValue>> unorderedItems,
   bool allowUpdates
)

Stopwatch sw = Stopwatch.StartNew();
var options = Options.Clone();
using (TempFile temp = new TempFile())
{
    //using (BPlusTree<int, string> data = Create(Options))
    using (BPlusTree<int, string> data = Create(options))
    {
        const bool bulk = true;
        Insert(data, CreateRandom(1000, 3000), bulk, false);

        data.EnableCount();
        Assert.AreEqual(1000, data.Count);

        Insert(data, CreateCount(data.Last().Key + 1, 1, 1000), bulk, true);
        Assert.AreEqual(2000, data.Count);

        Insert(data, CreateCount(data.Last().Key + 10001, -1, 1000), bulk, false);
        Assert.AreEqual(3000, data.Count);

        int lastKey = data.Last().Key;
        data.AddRange(CreateCount(1, 2, lastKey / 2), true);
    }
    temp.Dispose();
}
Trace.WriteLine("Inserted in " + sw.Elapsed);

Dim sw As Stopwatch = Stopwatch.StartNew()
Dim options As var = Options.Clone()
Using temp As New TempFile()
    'using (BPlusTree<int, string> data = Create(Options))
    Using data As BPlusTree(Of Integer, String) = Create(options)
        Const  bulk As Boolean = True
        Insert(data, CreateRandom(1000, 3000), bulk, False)

        data.EnableCount()
        Assert.AreEqual(1000, data.Count)

        Insert(data, CreateCount(data.Last().Key + 1, 1, 1000), bulk, True)
        Assert.AreEqual(2000, data.Count)

        Insert(data, CreateCount(data.Last().Key + 10001, -1, 1000), bulk, False)
        Assert.AreEqual(3000, data.Count)

        Dim lastKey As Integer = data.Last().Key
        data.AddRange(CreateCount(1, 2, lastKey / 2), True)
    End Using
    temp.Dispose()
End Using
Trace.WriteLine("Inserted in " + sw.Elapsed)