Need help optimizing URLEncode, or rewriting it

[INF3RN0666]

Hey, check out the following function. I did some testing on it and I think it could be a little faster. Now I don't know what else I can do to make it faster. I tried replacing the StrConv function to CopyMemoryStringToAny, and that did VERY LITTLE difference on a 100000 loop (like 100 ms at the most). Is there a better way to do it all together?

Public Function UrlEncode(ByVal urlText As String) As String
    Dim ANSI() As Byte
    Dim ASCII As Long
    Dim encText As String
    Dim I As Long
    
    On Error GoTo UrlEncode_Error
    
    ANSI = StrConv(urlText, vbFromUnicode)
    
    For I = 0 To UBound(ANSI)
        ASCII = (ANSI(I) + 2) Mod 256   'Roll over back to 0 past 255, else HEX and CHR won't work
        
        Select Case ASCII
            Case 48 To 57, 65 To 90, 97 To 122  'Letters and Numbers
                encText = encText & Chr(ASCII)
                
            Case 32     'Spaces
                encText = encText & "+"
                
            Case 0 To 16    'Low Hex characters
                encText = encText & "%0" & Hex(ASCII)
                
            Case Else   'Special Characters
                encText = encText & "%" & Hex(ASCII)
        End Select
    Next I
      
    UrlEncode = encText
    
    Exit Function
 
UrlEncode_Error:
    MsgBox "Error #:" & Err.Number & vbCrLf & "Procedure [UrlEncode] of Module [mNetFunctions]" & vbCrLf & "Description: " & Err.Description, vbOKOnly, "Error Handling"
End Function