fixed Base64Encoder big bug

[jacksonjim]

fixed Base64Encoder big bug

public sealed class NettyBase64Encoder : MessageToMessageEncoder
{
readonly bool breakLines;
readonly Base64Dialect dialect;

    public NettyBase64Encoder() : this(true) { }

    public NettyBase64Encoder(bool breakLines) : this(breakLines, Base64Dialect.STANDARD)
    {
    }

    public NettyBase64Encoder(bool breakLines, Base64Dialect dialect)
    {
        this.breakLines = breakLines;
        this.dialect = dialect;
    }

    public override bool IsSharable => true;

    protected override void Encode(IChannelHandlerContext context, IByteBuffer message, List<object> output)
    {
        output.Add(Base64.Encode(message, message.ReaderIndex, message.ReadableBytes, breakLines, dialect));
    }
}

[ghost]

All CLA requirements met.