Public Overloads Shared Function SHA256( _
   ByVal bytes As Stream _
) As Hash

public static Hash SHA256( 
   Stream bytes
)

Random r = new Random();
byte[] a = new byte[10], b = new byte[32];
r.NextBytes(a);
r.NextBytes(b);

Hash h1 = Hash.SHA256(a);
Hash h3 = h1.Combine(b);

Assert.AreEqual(h3.ToString(), Hash.SHA256(
    new CombinedStream(
        new MemoryStream(h1.ToArray()),
        new MemoryStream(Hash.SHA256(b).ToArray())//bytes combined are hashed first
        )).ToString());

Dim r As New Random()
Dim a As Byte() = New Byte(10) {}, b As Byte() = New Byte(32) {}
r.NextBytes(a)
r.NextBytes(b)

Dim h1 As Hash = Hash.SHA256(a)
Dim h3 As Hash = h1.Combine(b)

'bytes combined are hashed first
Assert.AreEqual(h3.ToString(), Hash.SHA256(New CombinedStream(New MemoryStream(h1.ToArray()), New MemoryStream(Hash.SHA256(b).ToArray()))).ToString())