@java.lang.Override
  public com.google.protobuf.ByteString getPageTokenBytes() {
    java.lang.Object ref = pageToken_;
    if (ref instanceof java.lang.String) {
      com.google.protobuf.ByteString b =
          com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
      pageToken_ = b;
      return b;
    } else {
      return (com.google.protobuf.ByteString) ref;
    }
  }
<pre>
Required. A page token, received from a previous `ListSources` call.
Provide this to retrieve the subsequent page.

When paginating, all other parameters provided to `ListSources` must
match the call that provided the page token.
</pre>

<code>string page_token = 3 [(.google.api.field_behavior) = REQUIRED];</code>

@return The bytes for pageToken.
java-vmmigration/proto-google-cloud-vmmigration-v1/src/main/java/com/google/cloud/vmmigration/v1/ListSourcesRequest.java