///<inheritdoc />
public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
{
ThrowIfDisposed();
if (_memoryStatus == MemoryFlag.AutoOverFlowToDisk && _isInMemory && count + UnderlyingStream.Position > _threshholdSize)
{
OverflowToPersistentStream();
}
return(UnderlyingStream.BeginWrite(buffer, offset, count, callback, state));
}