http2 crash when I use unicode in http header

When I am using unicode in http header

and When I use http2

Application asserted with

6 HPack::BitOStream::writeBits bitstreams.cpp 74 0x7ffff6ff7ca5
7 HPack::(anonymous namespace)::write_huffman_code huffman.cpp 362 0x7ffff6ff8a01
8 HPack::huffman_encode_string qarraydata.h 61 0x7ffff6ff8b0f
9 HPack::BitOStream::write bitstreams.cpp 117 0x7ffff6ff7e14
10 HPack::Encoder::encodeLiteralField hpack.cpp 403 0x7ffff6ff9e84
11 HPack::Encoder::encodeHeaderField hpack.cpp 299 0x7ffff6ffa00c
12 HPack::Encoder::encodeRequest hpack.cpp 163 0x7ffff6ffad21
13 QHttp2ProtocolHandler::sendHEADERS qhttp2protocolhandler.cpp 492 0x7ffff70045dd
14 QHttp2ProtocolHandler::sendRequest qhttp2protocolhandler.cpp 398 0x7ffff7009f3f
15 QHttpNetworkConnectionChannel::sendRequest qhttpnetworkconnectionchannel.cpp 258 0x7ffff701d719
16 QHttpNetworkConnectionPrivate::_q_startNextRequest qhttpnetworkconnection.cpp 1083 0x7ffff701c65d
17 QHttpNetworkConnection::qt_static_metacall qhttpnetworkconnection_p.h 167 0x7ffff701cde7
 

I attached example. It is just modified http example with 

request.setAttribute( QNetworkRequest::HTTP2AllowedAttribute, true );

request.setHeader( QNetworkRequest::ContentDispositionHeader, QStringLiteral("ššččč") );

All fine when I disable http2