code: public static Credentials credentials(final String scheme, final byte[] authToken) {
      MorePreconditions.checkNotBlank(scheme);
      Objects.requireNonNull(authToken);
  
      return new Credentials() {
        @Override public void authenticate(ZooKeeper zooKeeper) {
          zooKeeper.addAuthInfo(scheme, authToken);
        }
  
        @Override public String scheme() {
          return scheme;
        }
  
        @Override public byte[] authToken() {
          return authToken;
        }
  
        @Override public boolean equals(Object o) {
          if (!(o instanceof Credentials)) {
            return false;
          }
  
          Credentials other = (Credentials) o;
          return new EqualsBuilder()
              .append(scheme, other.scheme())
              .append(authToken, other.authToken())
              .isEquals();
        }
  
        @Override public int hashCode() {
          return Arrays.hashCode(new Object[] {scheme, authToken});
        }
      };
    }
docs: Creates a set of credentials for the given authentication {@code scheme}.
  
  @param scheme the scheme to authenticate with
  @param authToken the authentication token
  @return a set of credentials that can be used to authenticate the zoo keeper client