@java.lang.Override
  public int hashCode() {
    if (memoizedHashCode != 0) {
      return memoizedHashCode;
    }
    int hash = 41;
    hash = (19 * hash) + getDescriptor().hashCode();
    if (hasCollection()) {
      hash = (37 * hash) + COLLECTION_FIELD_NUMBER;
      hash = (53 * hash) + getCollection().hashCode();
    }
    if (hasUpdateMask()) {
      hash = (37 * hash) + UPDATE_MASK_FIELD_NUMBER;
      hash = (53 * hash) + getUpdateMask().hashCode();
    }
    hash = (29 * hash) + getUnknownFields().hashCode();
    memoizedHashCode = hash;
    return hash;
  }
<pre>
The list of fields to be updated.
- Unset `update_mask` or set `update_mask` to be a single "*" only will
  update all updatable fields with the value provided in `collection`.
- To update `display_name` value to empty string, set it in the
`collection`
  to empty string, and set `update_mask` with "display_name". Same applies
  to other updatable string fields in the `collection`.
</pre>

<code>.google.protobuf.FieldMask update_mask = 2;</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/UpdateCollectionRequest.java