code: public static ManagedChannel fromDefaultCreds(String fields) throws SSLException, IOException {
      return fromCreds(CredentialFactory.getApplicationDefaultCredentials(), fields);
    }
docs: Create a new gRPC channel to the Google Genomics API, using the application default credentials
  for auth.
  
  @param fields Which fields to return in the partial response, or null for none.
  @return The ManagedChannel.
  @throws SSLException
  @throws IOException