public void ProcessSecureData(ReadOnlySpan<char> sensitive)
{
    Span<byte> buffer = stackalloc byte[sensitive.Length * 2];
    try
    {
        // Perform cryptographic operations
        System.Text.Encoding.UTF8.GetBytes(sensitive, buffer);
        PerformOperation(buffer);
    }
    finally
    {
        // Overwrite memory to prevent data leakage after method returns
        buffer.Clear();
    }
}