capture stdout or stderr

[Emil via Digitalmars-d-learn]

is it possible to intercept the  STDOUT or STDERR and capture the 
output into a variable ?

some pseudocode to explain what I mean

string[] output_buffer;
stdout.capture_to(output_buffer);

writeln("test 1"); # not printed
writeln("test 2"); # not printed

stdout.release(output_buffer);

writeln("test 3"); # printed
writeln(output_buffer); # prints '["test 1","test 2"]'