static NanoHTTPD.Response serveFileWithName(File file) {
  ret serveFileWithName(file, file.getName());
}

static NanoHTTPD.Response serveFileWithName(File file, S name) {
  ret serveWithFileName_addName(serveFile(file), name);
}

static NanoHTTPD.Response serveWithFileName_addName(NanoHTTPD.Response r, S name) {
  r.addHeader("Content-Disposition", "inline; filename=\"" + name + "\""); // todo: encode special characters
  ret r;
}

static NanoHTTPD.Response serveFileWithName(File file, S name, S mimeType) {
  ret serveWithFileName_addName(serveFile(file, mimeType), name);
}

Began life as a copy of #1003197