@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(uri_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, uri_);
    }
    if (pageNumber_ != 0) {
      output.writeInt32(2, pageNumber_);
    }
    getUnknownFields().writeTo(output);
  }
<pre>
If the file was a PDF or TIFF, this field gives the page number within
the file used to produce the image.
</pre>

<code>int32 page_number = 2;</code>

@return The pageNumber.
java-vision/proto-google-cloud-vision-v1p4beta1/src/main/java/com/google/cloud/vision/v1p4beta1/ImageAnnotationContext.java