} else {
      // count how many bytes we'll need to express the length.
      val lengthBitCount = 64 - java.lang.Long.numberOfLeadingZeros(length)
      val lengthByteCount = (lengthBitCount + 7) / 8
      sink.writeByte(0b1000_0000 or lengthByteCount)
      for (shift in (lengthByteCount - 1) * 8 downTo 0 step 8) {
        sink.writeByte((length shr shift).toInt())
      }
    }

    // Write the payload.
    sink.writeAll(content)
  }

  override fun toString(): String = "$tagClass/$tag"

  companion object {
    const val TAG_CLASS_UNIVERSAL = 0b0000_0000
    const val TAG_CLASS_APPLICATION = 0b0100_0000
    const val TAG_CLASS_CONTEXT_SPECIFIC = 0b1000_0000
    const val TAG_CLASS_PRIVATE = 0b1100_0000

    const val TAG_END_OF_CONTENTS = 0L
  }

		// pointer to the scalarOrder field because comparing generic and
		// instantiated types is not supported.
		if &c.scalarOrder[0] == &p521Order[0] {
			key[0] &= 0b0000_0001
		}

		// In tests, rand will return all zeros and NewPrivateKey will reject
		// the zero key as it generates the identity as a public key. This also
		// makes this function consistent with crypto/elliptic.GenerateKey.