public Builder mergeSource(com.google.cloud.vision.v1p4beta1.ImageSource value) {
      if (sourceBuilder_ == null) {
        if (((bitField0_ & 0x00000002) != 0)
            && source_ != null
            && source_ != com.google.cloud.vision.v1p4beta1.ImageSource.getDefaultInstance()) {
          getSourceBuilder().mergeFrom(value);
        } else {
          source_ = value;
        }
      } else {
        sourceBuilder_.mergeFrom(value);
      }
      if (source_ != null) {
        bitField0_ |= 0x00000002;
        onChanged();
      }
      return this;
    }
<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>
java-vision/proto-google-cloud-vision-v1p4beta1/src/main/java/com/google/cloud/vision/v1p4beta1/Image.java