docs: function() {
          if (process.platform !== 'darwin') {
              return;
          }
  
          // top is running in logging mode, spewing process info to stdout every second.
          this._topConsole = child_process.spawn('/usr/bin/top', ['-l', '0', '-stats', 'pid,cpu,mem,command']);
          this._topConsole.stdout.on('data', _.bind(function(stdout) {
              var id = $$persistence.processId();
              if (!id) {
                  return;
              }
  
              // Find the line with the process id that matches what we're watching.
              stdout = stdout.toString();
              var lines = stdout.split('\n');
              var line = lines.filter(function(line) {
                  return line.indexOf(id) === 0;
              })[0];
              if (!line) {
                  return;
              }
              var parts = line.split(/\s+/g);
  
              // Add to the CPU history.
              var cpu = parseFloat(parts[1]);
              this._cpuFrame(cpu);
  
              // Add to the memory history.
              var memory = parts[2];
              var unit = 1;
              if (memory.indexOf('K') !== -1) {
                  unit = 1024;
              } else if (memory.indexOf('M') !== -1) {
                  unit = 1024 * 1024;
              } else if (memory.indexOf('G') !== -1) {
                  unit = 1024 * 1024 * 1024;
              }
              memory = memory.replace(/[\D]/g, '');
              memory = parseInt(memory) * unit;
              this._memoryFrame(memory);
  
          }, this));
      }