C#

public sealed class SqlManager
{
    private SqlManager(){}
    private static SqlManager instance;
    private static object syncRoot = new Object();
    public static SqlManager Instance
    {
        get
        {
            if(SqlManager.instance == null)
            {
                lock(syncRoot)
                {
                    if(SqlManager.instance == null)
                    {
                        SqlManager mgr = new SqlManager();
                        System.Threading.Thread.MemoryBarrier();
                        SqlManager.instance = mgr;
                    }
                }
            }
            return SqlManager.instance;
        }
    }
}

StreamingPlayer stmPlyr = new StreamingPlayer();
private void btnStartStream_Click(object sender, EventArgs e)
{
   PullAudioCallback cbk = new PullAudioCallback(someAudioCallBack);
   stmPlyr.Play(cbk);
}

private void someAudioCallBack(IntPtr data, int count)
{
// something here.
}