/// <summary>Write one object.</summary>
/// <remarks>
/// Write one object.
/// If the object was already written, this method does nothing and returns
/// quickly. This case occurs whenever an object was written out of order in
/// order to ensure the delta base occurred before the object that needs it.
/// </remarks>
/// <param name="otp">the object to write.</param>
/// <exception cref="System.IO.IOException">
/// the object cannot be read from the object reader, or the
/// output stream is no longer accepting output. Caller must
/// examine the type of exception and possibly its message to
/// distinguish between these cases.
/// </exception>
public void WriteObject(ObjectToPack otp)
{
packWriter.WriteObject(this, otp);
}