Set the value for this password.
The value will be copied by the password object.
Specify the length, for a non-nul-terminated password. Pass -1 as length if using a nul-terminated password,
and length will be calculated automatically. (Note that the terminating nul is not considered part of the password in this
case.)
| this |
a TlsPassword object |
| value |
the new password value |
| length |
the length of the password, or -1 |