* Bei `PUT`-Anfragen an `/items/{item_id}` den Body als JSON lesen:
    * Prüfen, ob er ein erforderliches Attribut `name` hat, das ein `str` sein muss.
    * Prüfen, ob er ein erforderliches Attribut `price` hat, das ein `float` sein muss.
    * Prüfen, ob er ein optionales Attribut `is_offer` hat, das ein `bool` sein muss, falls vorhanden.
    * All dies würde auch für tief verschachtelte JSON-Objekte funktionieren.
* Automatisch von und nach JSON konvertieren.

		Handle StatelessHandlerFn
		// OutCapacity is the output capacity on the caller.
		// If <= 0 capacity will be 1.
		OutCapacity int
	}

	// StreamHandlerFn must process a request with an optional initial payload.
	// It must keep consuming from 'in' until it returns.
	// 'in' and 'out' are independent.
	// The handler should never close out.
	// Buffers received from 'in'  can be recycled with PutByteBuffer.

	storageReadVersionRPC      = grid.NewSingleHandler[*grid.MSS, *FileInfo](grid.HandlerReadVersion, grid.NewMSS, func() *FileInfo { return &FileInfo{} })
	storageReadXLRPC           = grid.NewSingleHandler[*grid.MSS, *RawFileInfo](grid.HandlerReadXL, grid.NewMSS, func() *RawFileInfo { return &RawFileInfo{} })

    /**
     * Builds a project descriptor from the specified POM file.
     *
     * @param projectFile The POM file to build the project from, must not be {@code null}.
     * @param request The project building request that holds further parameters, must not be {@code null}.
     * @return The result of the project building, never {@code null}.

     *
     * @param model The model to validate, must not be {@code null}.
     * @param request The model building request that holds further settings, must not be {@code null}.
     * @param problems The container used to collect problems that were encountered, must not be {@code null}.
     */

   * does not include "was cancelled." To be explicit: If this method returns a non-null value,
   * then:
   *
   * <ul>
   *   <li>{@code isDone()} must return {@code true}
   *   <li>{@code isCancelled()} must return {@code false}
   *   <li>{@code get()} must not block, and it must throw an {@code ExecutionException} with the
   *       return value of this method as its cause
   * </ul>
   *

     * @param profiles The (read-only) list of profiles whose values should be injected, must not be <code>null</code>.
     * @param request The model building request that holds further settings, must not be {@code null}.
     * @param problems The container used to collect problems that were encountered, must not be {@code null}.
     */
    Model injectProfiles(

     *
     * @param model The model whose duplicate elements should be merged, must not be {@code null}.
     * @param request The model building request that holds further settings, must not be {@code null}.
     * @param problems The container used to collect problems that were encountered, must not be {@code null}.
     */

     *
     * @param profile The profile whose activation status should be determined, must not be {@code null}.
     * @param context The environmental context used to determine the activation status of the profile, must not be
     *            {@code null}.
     * @param problems The container used to collect problems (e.g. bad syntax) that were encountered, must not be
     *            {@code null}.

     *
     * @param session The session to use to resolve the model, must not be {@code null}.
     * @param parent The parent coordinates to resolve, must not be {@code null}.
     * @param modified a holder for the updated parent, must not be {@code null}.
     * @return The source of the requested POM, never {@code null}.