code: private Collection<SwimMember> selectRandomMembers(int count, ImmutableMember exclude) {
      List<SwimMember> members = this.members.values().stream()
          .filter(member -> !member.id().equals(localMember.id()) && !member.id().equals(exclude.id()))
          .collect(Collectors.toList());
      Collections.shuffle(members);
      return members.subList(0, Math.min(members.size(), count));
    }
docs: Selects a set of random members, excluding the local member and a given member.
  
  @param count count the number of random members to select
  @param exclude the member to exclude
  @return members a set of random members