code: public static ManagedChannel createChannelPool(final String host, final BigtableOptions options)
        throws IOException, GeneralSecurityException {
      return createChannelPool(host, options, 1);
    }
docs: Create a new {@link com.google.cloud.bigtable.grpc.io.ChannelPool}, with auth headers.
  
  @param host a {@link String} object.
  @param options a {@link BigtableOptions} object.
  @return a {@link ChannelPool} object.
  @throws IOException if any.
  @throws GeneralSecurityException