@java.lang.Override
    public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
      return super.setUnknownFields(unknownFields);
    }
<pre>
Fraction of importance of this salient region with respect to the original
image.
</pre>

<code>float importance_fraction = 3;</code>

@return This builder for chaining.
java-vision/proto-google-cloud-vision-v1/src/main/java/com/google/cloud/vision/v1/CropHint.java