@Override
    public void initChannel(SocketChannel ch) throws Exception {
        final Http2Connection connection = new DefaultHttp2Connection(false);
        connectionHandler = new HttpToHttp2ConnectionHandlerBuilder()
            .frameListener(
                new DelegatingDecompressorFrameListener(connection, new InboundHttp2ToHttpAdapterBuilder(connection)
                    .maxContentLength(transportConfig.getPayload()).propagateSettings(true).build()))
            .connection(connection).build();
        responseHandler = new Http2ClientChannelHandler();
        settingsHandler = new Http2SettingsHandler(ch.newPromise());
        String protocol = transportConfig.getProviderInfo().getProtocolType();
        if (RpcConstants.PROTOCOL_TYPE_H2.equals(protocol)) {
            configureSsl(ch);
        } else if (RpcConstants.PROTOCOL_TYPE_H2C.equals(protocol)) {
            if (!useH2cPriorKnowledge) {
                configureClearTextWithHttpUpgrade(ch);
            } else {
                configureClearTextWithPriorKnowledge(ch);
            }
        }
    }
Does the H2C Protocol Use the Prior-Knowledge Method to Start Http2
remoting/remoting-http/src/main/java/com/alipay/sofa/rpc/transport/http/Http2ClientInitializer.java