Faster ways to redirect stdout of child process to file

[Thomas Mader via Digitalmars-d-learn]

I use

        auto pipes = pipeProcess( cmd, Redirect.stdout | 
Redirect.stderr );

to redirect stdout of the newly created subprocess via pipes to a 
file. The redirect itself happens in a newly created thread 
(because I need to wait for the subprocess to finish to take the 
exact elapsed time) doing basically:

        pipes.stdout.byChunk( 1024 * 1024 ).copy( 
cof.lockingTextWriter() );

This happens to use much of my CPU time (~25%). I wonder if there 
is no faster way to do this.
I use this method because I want to be platform independent.

Thomas