@CanIgnoreReturnValue
    public Builder setCrtCoefficient(SecretBigInteger qInv) {
      this.qInv = Optional.of(qInv);
      return this;
    }
Sets the CRT coefficient qInv.

<p>See https://datatracker.ietf.org/doc/html/rfc7518#section-6.3.2.6.

<p>This is required.
java_src/src/main/java/com/google/crypto/tink/jwt/JwtRsaSsaPkcs1PrivateKey.java