in the Decode method on line 78 `buffer = (buffer << 5) | (ulong)(DecodingTable[index[j]] & 0x1f);` causes a compiler warning [CS0675](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-messages/cs0675?f1url=%3FappId%3Droslyn%26k%3Dk(CS0675)) can this be fixed? thoughts on how?
