unescapeBytes
Unescapes a segment of an escaped string as binary data.
Note that in contrast to g_uri_unescape_string(), this does allow nul bytes to appear in the output.
If any of the characters in @illegal_characters appears as an escaped character in @escaped_string, then that is an error and null will be returned. This is useful if you want to avoid for instance having a slash being expanded in an escaped path element, which might confuse pathname handling.
Return
an unescaped version of @escaped_string or null on error (if decoding failed, using %G_URI_ERROR_FAILED error code). The returned #GBytes should be unreffed when no longer needed.
Since
2.66
Parameters
A URI-escaped string
the length (in bytes) of @escaped_string to escape, or -1 if it is nul-terminated.
a string of illegal characters not to be allowed, or null.