public Builder setPageTokenBytes(com.google.protobuf.ByteString value) {
      if (value == null) {
        throw new NullPointerException();
      }
      checkByteStringIsUtf8(value);
      pageToken_ = value;
      bitField0_ |= 0x00000008;
      onChanged();
      return this;
    }
<pre>
Token identifying the page of results to return. If provided, use the
value of the `next_page_token` field from a previous request.
</pre>

<code>string page_token = 4;</code>

@param value The bytes for pageToken to set.
@return This builder for chaining.
java-trace/proto-google-cloud-trace-v1/src/main/java/com/google/devtools/cloudtrace/v1/ListTracesRequest.java