private static unsafe void WriteToBlobAsync(CloudPageBlob blob, IntPtr sourceAddress, ulong destinationAddress, uint numBytesToWrite, IOCompletionCallback callback, IAsyncResult asyncResult)
{
// Even though Azure Page Blob does not make use of Overlapped, we populate one to conform to the callback API
Overlapped ov = new Overlapped(0, 0, IntPtr.Zero, asyncResult);
NativeOverlapped * ovNative = ov.UnsafePack(callback, IntPtr.Zero);
UnmanagedMemoryStream stream = new UnmanagedMemoryStream((byte *)sourceAddress, numBytesToWrite);
blob.BeginWritePages(stream, (long)destinationAddress, null, ar =>
{
try
{
blob.EndWritePages(ar);
}
// I don't think I can be more specific in catch here because no documentation on exception behavior is provided
catch (Exception e)
{
Trace.TraceError(e.Message);
// Is there any documentation on the meaning of error codes here? The handler suggests that any non-zero value is an error
// but does not distinguish between them.
callback(1, numBytesToWrite, ovNative);
}
callback(0, numBytesToWrite, ovNative);
}, asyncResult);
}
