Using the reduce() method should be a good way to add the total number of items that are loaded in the table. Here is a quick example of the syntax for the reduce() method:

const newValue = arr.reduce(function(previousValue, currentValue, index, array) {
  // Do stuff with previousValue and currentValue (index, array, and initialValue are optional)
}, initialValue);

newValue- the new number, array, string, or object that is returned
arr - the array being operated on
previousValue - the returned value of the previous iteration
currentValue - the current item in the array
index - the index of the current item
array - the original array on which reduce() was called
initialValue - a number, array, string, or object that serves as an initial value for the eventual output

In our use case, the only props that we need are previousValue, currentValue, and initialValue. previousValue and currentValue are both required but initialValue is necessary because when the array of items is first created it is an empty array, so it has no initial value to use for the previousValue prop. Adding the number of total items using this method should be simple because the data is already in an array and react-table also returns the filtered rows as an array. The next steps are to figure out the proper way to implement the UI. Here is how it could look like as a part of the QueueSelector. The only problem with displaying it here is that the data passed to the QueueSelector doesn't have access to the number of filtered rows. The likely solution to this is to create a separate component.