code: function post_process(){
        var error = false;
        var invalid_reasons = []
  
        if (read_result.riff_head != "RIFF")  invalid_reasons.push("Expected \"RIFF\" string at 0" )
        if (read_result.wave_identifier != "WAVE") invalid_reasons.push("Expected \"WAVE\" string at 4")
        if (read_result.fmt_identifier != "fmt ") invalid_reasons.push("Expected \"fmt \" string at 8")
        if (
          (read_result.audio_format != 1) &&        // Wav
          (read_result.audio_format != 65534)  &&   // Extensible PCM
          (read_result.audio_format != 2)  &&       // Wav
          (read_result.audio_format != 22127)  &&   // Vorbis ?? (issue #11)
          (read_result.audio_format != 3))          // Wav
                invalid_reasons.push("Unknown format: "+read_result.audio_format)
        if ((read_result.chunk_size + 8) !== stats.size) invalid_reasons.push("chunk_size does not match file size")
        //if ((read_result.data_identifier) != "data") invalid_reasons.push("Expected data identifier at the end of the header")
  
        if (invalid_reasons.length > 0) error = true;
  
        if (error) return cb({
          error : true,
          invalid_reasons: invalid_reasons,
          header: read_result,
          stats: stats
        });
  
        cb(null, {
          header: read_result,
          stats: stats,
          duration: ((read_result.chunk_size) / (read_result.sample_rate * read_result.num_channels * (read_result.bits_per_sample / 8)))
        });
      }
docs: end fs.read