code: public void processConnectionPrefaceMagic() throws Http2Exception {
          connection_preface_string_rcvd = true;
          H2StreamProcessor controlStream = createNewInboundLink(0);
          controlStream.completeConnectionPreface();
          connection_preface_sent = true;
      }
docs: Handle the receipt of the MAGIC string from the client: initialize the control stream 0 and and send out a settings frame to
  acknowledge the MAGIC string
  
  @throws StreamClosedException