c# - XmlWriter async methods -

i have found example of async using of xmlwriter within msdn documentation http://msdn.microsoft.com/en-us/library/system.xml.xmlwriter.aspx

async task testwriter(stream stream)  {     xmlwritersettings settings = new xmlwritersettings();     settings.async = true;     using (xmlwriter writer = xmlwriter.create(stream, settings)) {         await writer.writestartelementasync("pf", "root", "http://ns");         await writer.writestartelementasync(null, "sub", null);         await writer.writeattributestringasync(null, "att", null, "val");         await writer.writestringasync("text");         await writer.writeendelementasync();         await writer.writeprocessinginstructionasync("pname", "pvalue");         await writer.writecommentasync("cvalue");         await writer.writecdataasync("cdata value");         await writer.writeendelementasync();         await writer.flushasync();     } } 

all know threads , async programming said me slow code , using synchronous write methods faster. have modified code , tested it. have found i'm right , synchronous code faster in 3-4 times on files more 100mb , more 8-10 times faster on files less 10mb on env.

so question there scenario such code usable , gives reasonable profit?

first off, have question benchmarking. 3-4 times slower on 100mb files significant.

but regardless, async not doing things faster. it's doing else while operation going on. on client side, benefit of responsiveness; on server side, benefit of scalability.

the tradeoff operation slower (but should little slower, not 3-4 times slower). it's you're not using asynchronous stream writing (you have open file stream asynchronously asynchronous stream).