Public Overloads Sub Write( _
   ByVal position As Long, _
   ByVal buffer() As Byte, _
   ByVal offset As Integer, _
   ByVal length As Integer _
) 

public void Write( 
   long position,
   byte[] buffer,
   int offset,
   int length
)

using (TestStream io = new TestStream())
using (BackgroundWriter wtr = new BackgroundWriter(io))
{
    wtr.Write(0L, new byte[100], 0, 100);
    wtr.Perform(s => Thread.Sleep(50));
    wtr.Write(100L, new byte[] { 99 }, 0, 1);
    wtr.Write(100L, new byte[] { 42, 43 }, 0, 2);

    // Read scans the pending writes for writes at the provided offset and returns the last result
    byte[] read = new byte[100];
    Assert.AreEqual(2, wtr.Read(100L, read, 0, 100));
    Assert.AreEqual(42, (int)read[0]);
    Assert.AreEqual(43, (int)read[1]);
}

Using io As New TestStream()
    Using wtr As New BackgroundWriter(io)
        wtr.Write(0L, New Byte(100) {}, 0, 100)
        wtr.Perform(Function(s) Thread.Sleep(50))
        wtr.Write(100L, New Byte() {99}, 0, 1)
        wtr.Write(100L, New Byte() {42, 43}, 0, 2)

        ' Read scans the pending writes for writes at the provided offset and returns the last result
        Dim read As Byte() = New Byte(100) {}
        Assert.AreEqual(2, wtr.Read(100L, read, 0, 100))
        Assert.AreEqual(42, DirectCast(read(0), Integer))
        Assert.AreEqual(43, DirectCast(read(1), Integer))
    End Using
End Using