code: func (writer *sparseWriter) Append(k, idx uint32, rho uint8) {
  	if writer.hasCurrVal {
  		if idx == writer.currIdx {
  			if rho > writer.currRho {
  				writer.currRho = rho
  				writer.currVal = k
  			}
  			return
  		} else {
  			writer.commit()
  		}
  	}
  
  	writer.hasCurrVal = true
  	writer.currVal = k
  	writer.currIdx = idx
  	writer.currRho = rho
  }
docs: // This takes the index and rho well so it can easily discard duplicate indexes
  // and pick the biggest rho among the duplicates since tmpSet is sorted by index
  // but not by rho.