code: func (s *Session) BuildInfo() (info BuildInfo, err error) {
  	err = s.Run(bson.D{{"buildInfo", "1"}}, &info)
  	if len(info.VersionArray) == 0 {
  		for _, a := range strings.Split(info.Version, ".") {
  			i, err := strconv.Atoi(a)
  			if err != nil {
  				break
  			}
  			info.VersionArray = append(info.VersionArray, i)
  		}
  	}
  	for len(info.VersionArray) < 4 {
  		info.VersionArray = append(info.VersionArray, 0)
  	}
  	if i := strings.IndexByte(info.GitVersion, ' '); i >= 0 {
  		// Strip off the " modules: enterprise" suffix. This is a _git version_.
  		// That information may be moved to another field if people need it.
  		info.GitVersion = info.GitVersion[:i]
  	}
  	return
  }
docs: // BuildInfo retrieves the version and other details about the
  // running MongoDB server.