anchor.diff:      let ensureDirectoryExists directoryExists createDirectory path =
           if not (directoryExists path) then
               createDirectory path
  +
  
positive.code:         | ex -> CouldNotDeleteSource { Request = moveRequest; Message = ex.Message } |> Failure
  
      let compareFiles readAllBytes moveRequest =
          let sourceStream = readAllBytes moveRequest.Source
          let destinationStream = readAllBytes moveRequest.Destination
          if sourceStream = destinationStream then
              Success moveRequest
          else
              BytesDidNotMatch moveRequest |> Failure
  
      let copyToDestination ensureDirectoryExists copy moveRequest =
          ensureDirectoryExists moveRequest.Destination
  
negative.code: 
  open Muffin.Pictures.Archiver.Domain
  open Muffin.Pictures.Archiver.Rop
  
  open System.IO // eventually this should be moved out.
  
  module FileMover =
  
  