protected static ClientRequestContext newDerivedContext(ClientRequestContext ctx,
                                                            @Nullable HttpRequest req,
                                                            @Nullable RpcRequest rpcReq,
                                                            boolean initialAttempt) {
        return ClientUtil.newDerivedContext(ctx, req, rpcReq, initialAttempt);
    }
Creates a new derived {@link ClientRequestContext}, replacing the requests.
If {@link ClientRequestContext#endpointGroup()} exists, a new {@link Endpoint} will be selected.
core/src/main/java/com/linecorp/armeria/client/retry/AbstractRetryingClient.java