docs: function() {
      var groupId = getString(libsignal.crypto.getRandomBytes(16));
      return this.getGroup(groupId).then(function(group) {
        if (group === undefined) {
          return groupId;
        } else {
          console.warn("group id collision"); // probably a bad sign.
          return this.generateNewGroupId();
        }
      });
    }