通知用户模型下载情况

<style>   progress[hidden] ~ label {     display: none;   } </style>  <button type="button">Create LanguageModel session</button> <progress hidden id="progress" value="0"></progress> <label for="progress">Model download progress</label> 

const createButton = document.querySelector('.create'); const promptButton = document.querySelector('.prompt'); const progress = document.querySelector('progress'); const output = document.querySelector('output');  let sessionCreationTriggered = false; let localSession = null;  const createSession = async (options = {}) => {   if (sessionCreationTriggered) {     return;   }    progress.hidden = true;   progress.value = 0;    try {     if (!('LanguageModel' in self)) {       throw new Error('LanguageModel is not supported.');     }      const availability = await LanguageModel.availability();     if (availability === 'unavailable') {       throw new Error('LanguageModel is not available.');     }      let modelNewlyDownloaded = false;     if (availability !== 'available') {       modelNewlyDownloaded = true;       progress.hidden = false;     }     console.log(`LanguageModel is ${availability}.`);     sessionCreationTriggered = true;      const llmSession = await LanguageModel.create({       monitor(m) {         m.addEventListener('downloadprogress', (e) => {           progress.value = e.loaded;           if (modelNewlyDownloaded && e.loaded === 1) {             // The model was newly downloaded and needs to be extracted             // and loaded into memory, so show the undetermined state.             progress.removeAttribute('value');           }         });       },       ...options,     });      sessionCreationTriggered = false;     return llmSession;   } catch (error) {     throw error;   } finally {     progress.hidden = true;     progress.value = 0;   } };  createButton.addEventListener('click', async () => {   try {     localSession = await createSession({       expectedInputs: [{ type: 'text', languages: ['en'] }],       expectedOutputs: [{ type: 'text', languages: ['en'] }],     });     promptButton.disabled = false;   } catch (error) {     output.textContent = error.message;   } });  promptButton.addEventListener('click', async () => {   output.innerHTML = '';   try {     const stream = localSession.promptStreaming('Write me a poem');     for await (const chunk of stream) {       output.append(chunk);     }   } catch (err) {     output.textContent = err.message;   } });