public boolean hasSource() {
      return ((bitField0_ & 0x00000002) != 0);
    }
<pre>
Google Cloud Storage image location, or publicly-accessible image
URL. If both `content` and `source` are provided for an image, `content`
takes precedence and is used to perform the image annotation request.
</pre>

<code>.google.cloud.vision.v1p4beta1.ImageSource source = 2;</code>

@return Whether the source field is set.
java-vision/proto-google-cloud-vision-v1p4beta1/src/main/java/com/google/cloud/vision/v1p4beta1/Image.java