public ApiFuture<GenerateContentResponse> generateContentAsync(Content content)
      throws IOException {
    return generateContentAsync(Arrays.asList(content));
  }
Asynchronously generates content from generative model given a single Content.

@param content a {@link com.google.cloud.vertexai.api.Content} to send to the generative model.
    The role of the content is "user".
@return a {@link com.google.api.core.ApiFuture} represents the response of an asynchronous
    generateContent request
@throws IOException if an I/O error occurs while making the API call
java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/GenerativeModel.java