ProxyContext.sendResponse is not completed if the body is set to null

[tsegismont]

Consider this method that configures the response:

  private static void setReturnAsNotChanged(ProxyContext context) {
    // @formatter:off
    context.response()
        .setBody(null)
        .setStatusCode(Response.Status.NOT_MODIFIED.getStatusCode())
        .setStatusMessage(Response.Status.NOT_MODIFIED.getReasonPhrase())
        .headers()
            .remove(HttpHeaders.CONTENT_LENGTH)
            .remove(HttpHeaders.CONTENT_TYPE)
            .remove(HttpHeaders.CONTENT_ENCODING);
    // @formatter:on
  }

The body is set to null because the user doesn't want to send anything to the client.

When context.sendResponse() is invoked, the returned future is never completed.

This happens because the completionHander is not invoked when the body is null:

vertx-http-proxy/src/main/java/io/vertx/httpproxy/impl/ProxiedResponse.java

Lines 219 to 222 in 2217655

	if (body == null) {
	proxiedResponse.end();
	return;
	}

[tsegismont]

Fixed by #112