Sampler/Schema Scanner - no further processing within transformer once 'first N features' met

Often, I’m dealing with large datasets and I want to do a quick comparison of the schemas. I only want one record from each. I appreciate that you can set Schema Scanner or Sampler to only sample one record, but it still processes the remaining features to an output port, which is wasting resource in many cases. 

How about a setting in both made available, that just takes the first (specified) number of features and then stops reading from the source?