RestEasy Client Framework throws null point exception when the @CookieParam() is null

If I have a remote interface defined as

<code>
@POST
@Path("/myCookie")
public ClientResponse<String> postWithCookie(@CookieParam("testCookie") String testCookie);
</code>

in the initial call, when there is no cookie was set, resteasy will throw NPE.
if the cookie was set already, then the request works.

<code>java.lang.NullPointerException
at org.jboss.resteasy.client.ClientRequest.toString(ClientRequest.java:213)
at org.jboss.resteasy.client.ClientRequest.cookie(ClientRequest.java:280)
at org.jboss.resteasy.client.core.marshallers.CookieParamMarshaller.build(CookieParamMarshaller.java:34)
at org.jboss.resteasy.client.core.ClientInvoker.createRequest(ClientInvoker.java:121)
at org.jboss.resteasy.client.core.ClientInvoker.invoke(ClientInvoker.java:87)
at org.jboss.resteasy.client.core.ClientProxy.invoke(ClientProxy.java:72)</code>