//
  // Certificate signers may not honor this field for various reasons:
  //
  //   1. Old signer that is unaware of the field (such as the in-tree
  //      implementations prior to v1.22)
  //   2. Signer whose configured maximum is shorter than the requested duration
  //   3. Signer whose configured minimum is longer than the requested duration
  //

  // Value must be non-negative integer. The value zero indicates delete immediately.
  // If this value is nil, the default grace period will be used instead.
  // The grace period is the duration in seconds after the processes running in the carp are sent
  // a termination signal and the time when the processes are forcibly halted with a kill signal.