    } else {
      formData = MultipartFormData()
    }

    // Make sure all fields for files are set to null, or the server won't look
    // for the files in the rest of the form data
    let fieldsForFiles = Set(files.map { $0.fieldName }).sorted()
    var fields = self.requestBodyCreator.requestBody(for: operation, sendOperationIdentifiers: shouldSendOperationID)
    var variables = fields["variables"] as? GraphQLMap ?? GraphQLMap()
    for fieldName in fieldsForFiles {
      if
        let value = variables[fieldName],