Knowledge base

Dim verifier = New EmailVerifier()
Dim result = verifier.Verify("john@example.org", VerificationLevel.Mailbox)

If (result.IsSuccess) Then
    Console.WriteLine("Mailbox verification test succeeded!")
Else
    ' The test failed. Let's see why...

    If (result.IsSyntaxFailure) Then
        ' The e-mail address is not syntactically valid
        ' TODO: Discard this address immediately
    ElseIf (result.IsTimeoutFailure) Then
        ' It failed because of a timeout, thus it could be valid
        ' TODO: Save a reference to this address for future retries
    ElseIf (result.IsNetworkFailure) Then
        ' It failed because of a network failure: chances are high that this
		' address is not valid!

        ' TODO: Discard this address or save it for future retries
    End If

    ' TODO: Test fo other failure types and act accordingly
End If