There are several custom response classes you can use to create an instance and return them directly from your *path operations*.

Read more about it in the [FastAPI docs for Custom Response - HTML, Stream, File, others](https://fastapi.tiangolo.com/advanced/custom-response/).

You can import them directly from `fastapi.responses`:

```python
from fastapi.responses import (
    FileResponse,
    HTMLResponse,

        stats.put("fs", getFsObj());
        return asJson(new ApiStatsResponse().stats(stats).status(ApiResult.Status.OK).result());
    }

    private FsObj[] getFsObj() {
        return Arrays.stream(File.listRoots()).map(f -> {
            final FsObj fsObj = new FsObj();
            fsObj.path = f.getAbsolutePath();
            fsObj.free = f.getFreeSpace();
            fsObj.total = f.getTotalSpace();

 */
package org.codelibs.fess.app.web.api.admin.reqheader;

import static org.codelibs.fess.app.web.admin.reqheader.AdminReqheaderAction.getRequestHeader;

import java.util.List;
import java.util.stream.Collectors;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.fess.app.pager.ReqHeaderPager;
import org.codelibs.fess.app.service.RequestHeaderService;

 */
package org.codelibs.fess.app.web.api.admin.webauth;

import static org.codelibs.fess.app.web.admin.webauth.AdminWebauthAction.getWebAuthentication;

import java.util.List;
import java.util.stream.Collectors;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.fess.app.pager.WebAuthPager;
import org.codelibs.fess.app.service.WebAuthenticationService;

  private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();
    stream.writeObject(elementSet().comparator());
    Serialization.writeMultiset(this, stream);
  }

  @J2ktIncompatible
  @GwtIncompatible // java.io.ObjectInputStream
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    stream.defaultReadObject();

  }

  @Override
  public boolean wasStreamClosed() {
    return byteSink.wasStreamClosed();
  }

  @Override
  public Writer openStream() throws IOException {
    // using TestByteSink's output stream to get option behavior, so flush to it on every write
    return new FilterWriter(new OutputStreamWriter(byteSink.openStream(), UTF_8)) {
      @Override
      public void write(int c) throws IOException {
        super.write(c);

	defaultQuoteEscapeCharacter = `"`
	defaultCommentCharacter     = "#"

	asneeded = "asneeded"
)

// ReaderArgs - represents elements inside <InputSerialization><CSV> in request XML.
type ReaderArgs struct {
	FileHeaderInfo             string `xml:"FileHeaderInfo"`
	RecordDelimiter            string `xml:"RecordDelimiter"`
	FieldDelimiter             string `xml:"FieldDelimiter"`

        saveLayout(writer, typed);
    }

    /**
     * Store a properties into a output stream, preserving comments, special character, etc.
     * This method is mainly to be compatible with the java.util.Properties class.
     *
     * @param os an output stream.
     * @param comment this parameter is ignored as this Properties
     * @throws IOException If storing fails
     */

> BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
> LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
> CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
> ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

func (e metaCacheEntry) hasPrefix(s string) bool {
	return strings.HasPrefix(e.name, s)
}

// matches returns if the entries have the same versions.
// If strict is false we allow signatures to mismatch.
func (e *metaCacheEntry) matches(other *metaCacheEntry, strict bool) (prefer *metaCacheEntry, matches bool) {
	if e == nil && other == nil {
		return nil, true
	}
	if e == nil {
		return other, false
	}
	if other == nil {