I am writing a manual where I include code snippets with typefile. Some of the code snippets contain text in Japanese

but don't appear in the PDF document as typefile seems to skip the Japanese characters

MWE

file cjk.asy

========

Label L;

L = Label("\\begin{CJK}{UTF8}{gbsn}{\\CJKfamily{gbsn}여보세요 \\end{CJK}");

label(L);

shipout();

main file

=======

\starttext

\typefile[C][]{cjk.asy}

\stoptext