Performance regression in version 4.4.2

### Version

4.4.2

### Context

After upgrading Vert.x from 3.9.13 to 4.4.2, we found a performance degradation in one of our APIs that uses kryo serialization and chunked encoding for the response content. The API also has mTLS enabled for communicating to the server. The performance degradation was in the form of a 250% increase in latency for the API as seen on the client.

### Do you have a reproducer?

No.

### Steps to reproduce

1. HTTPS Client with `application/x-kryo` set in the request header.
2. HTTPS Server that is able to serialize the response using kryo and chunked encoding enabled.
3. Compare results using 3.9.13 and 4.4.2.

### Extra

* Linux kernel version 4.1.12
* Java 8