*   [0, 255] for unsigned, num_bits = 8.

If range_given == False, the initial input_min, input_max will be determined
automatically as the minimum and maximum values in the input tensor, otherwise
the specified values of input_min, input_max are used.

Note: If the input_min, input_max are specified, they do not need to equal the
actual minimum and maximum values in the tensor. e.g. in some cases it may be