def add!(&blk)
      t = Benchmark.measure(&blk)
      @utime  = utime + t.utime
      @stime  = stime + t.stime
      @cutime = cutime + t.cutime
      @cstime = cstime + t.cstime
      @real   = real + t.real
      self
    end
def add!(&blk)
      t = Benchmark.measure(&blk)
      @utime  = utime + t.utime
      @stime  = stime + t.stime
      @cutime = cutime + t.cutime
      @cstime = cstime + t.cstime
      @real   = real + t.real
      self
    end
An in-place version of #add.