code: function(cb_) {
        console.log('Extracting ' + path.join(THRUST_PATH, 
                                              THRUST_RELEASE_FILENAME));
        if(os.platform() === 'darwin') {
          var unzip_p = require('child_process').spawn('unzip', 
            [ '-oqq', path.join(THRUST_PATH, THRUST_RELEASE_FILENAME) ], {
              cwd: THRUST_PATH
          });
          unzip_p.on('close', function (code) {
            if(code !== 0) {
              return cb_(common.err('Extraction failed with code: ' + code,
                                    'boostrap:failed_extraction'));
            }
            return cb_();
          });
        }
        else {
          async.series([
            function(cb_) {
              fs.createReadStream(path.join(THRUST_PATH, THRUST_RELEASE_FILENAME))
                .on('error', cb_)
                .pipe(unzip.Extract({
                  path: THRUST_PATH
                }).on('close', cb_));
            },
            function(cb_) {
              if(os.platform() === 'linux') {
                var exec_path = path.join(THRUST_PATH, 'thrust_shell');
                fs.chmod(exec_path, 0755, cb_);
              }
              else {
                return cb_();
              }
            }
          ], cb_);
        }
      }
docs: /* Extract thrust in THRUST_PATH