public Builder setVersionToken(com.google.protobuf.ByteString value) {
      if (value == null) {
        throw new NullPointerException();
      }
      versionToken_ = value;
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
The current version token of the client for the requested list (the
client version that was received from the last successful diff).
If the client does not have a version token (this is the first time calling
ComputeThreatListDiff), this may be left empty and a full database
snapshot will be returned.
</pre>

<code>bytes version_token = 2;</code>

@param value The versionToken to set.
@return This builder for chaining.
java-webrisk/proto-google-cloud-webrisk-v1/src/main/java/com/google/webrisk/v1/ComputeThreatListDiffRequest.java