(it's still very slow)

cannot be found.

I suppose that the author would like to truncate the type name, not get a
string of 100/200 characters.

PyOS_snprintf() to avoid temporary buffer allocated on the stack and a
conversion from bytes to Unicode.

PyOS_snprintf().

doesn't have PY_SSIZE_T_CLEAN define and the size doesn't fit in an int
(length bigger than 2^31-1 bytes).