SwiftUI ShareLink set file name

I'm using the ShareLink to share an FileDocument which contains a String. The FileDocument is conform to the Transferable protocol.

This is the FileDocument Struct:

struct TransferableDocument: FileDocument, Transferable {

  static var transferRepresentation: some TransferRepresentation
  {
      DataRepresentation(exportedContentType: .text) { log in
          log.convertToData()
      }
  }

  // tell the system to support only text
  static var readableContentTypes: [UTType] = [.text]

  // by default the document is empty
  var text = ""

  // this initializer creates a empty document
  init(initialText: String = "") {
      text = initialText
  }

  // this initializer loads data that has been saved previously
  init(configuration: ReadConfiguration) throws {
      if let data = configuration.file.regularFileContents {
          text = String(decoding: data, as: UTF8.self)
      }
  }

  // this will be called when the system wants to write the data to disk
  func fileWrapper(configuration: WriteConfiguration) throws -> FileWrapper {
      let data = Data(text.utf8)
      return FileWrapper(regularFileWithContents: data)
  }

  func convertToData() -> Data
  {
      return text.data(using: .ascii) ?? Data()
  }
}

And this is the ShareLink:

var doc: TransferableDocument
{
    return TransferableDocument(initialText: "I'm a String")
}

ShareLink(item: doc ,preview: SharePreview("logfile")) 
{
    Text("Share")
}

When using AirDrop, the filename is set to the SharePreview title, in this case "logfile". When sharing it to Apps like Mail, the filename is simply set to "text".

Is there any way to set a default filename?