"Not before" time claim; specifies when this token should start being valid (in seconds since Unix epoch). <p>
If you want to omit this, set this to <code>0</code>, but do NOT FORGET to set it to something,
otherwise it will be set to whatever random value was in the memory where this variable resides.
@see https://tools.ietf.org/html/rfc7519#section-4.1.5
"Not before" time claim; specifies when this token should start being valid (in seconds since Unix epoch). <p> If you want to omit this, set this to <code>0</code>, but do NOT FORGET to set it to something, otherwise it will be set to whatever random value was in the memory where this variable resides. @see https://tools.ietf.org/html/rfc7519#section-4.1.5