Spring AI Modify the DefaultToolCallResultConverter.convert method and add filtering code

If the method returns a value of Mono type, the calling effect cannot be achieved.
So the modifications are as follows:

public String convert(@Nullable Object result, @Nullable Type returnType) {

       // This is the newly added filtering code used to obtain the real values in Mono
       **if (result instanceof Mono<?>) {
            result = ((Mono<?>) result).block();
        }**

        if (returnType == Void.TYPE) {
            logger.debug("The tool has no return type. Converting to conventional response.");
            return JsonParser.toJson("Done");
        } else if (result instanceof RenderedImage) {
            ByteArrayOutputStream buf = new ByteArrayOutputStream(4096);

            try {
                ImageIO.write((RenderedImage)result, "PNG", buf);
            } catch (IOException var5) {
                return "Failed to convert tool result to a base64 image: " + var5.getMessage();
            }

            String imgB64 = Base64.getEncoder().encodeToString(buf.toByteArray());
            return JsonParser.toJson(Map.of("mimeType", "image/png", "data", imgB64));
        } else {
            logger.debug("Converting tool result to JSON.");
            return JsonParser.toJson(result);
        }
    }