val tag: Long,
  /** Encode and decode the value once tags are handled. */
  private val codec: Codec<T>,
  /** True if the default value should be used if this value is absent during decoding. */
  val isOptional: Boolean = false,
  /** The value to return if this value is absent. Undefined unless this is optional. */
  val defaultValue: T? = null,
  /** True to set the encoded or decoded value as the type hint for the current SEQUENCE. */

    isOptional: Boolean = false,
    optionalValue: Any? = null,
  ): DerAdapter<Any?> {
    return object : DerAdapter<Any?> {
      override fun matches(header: DerHeader): Boolean = true

      override fun toDer(
        writer: DerWriter,
        value: Any?,
      ) {
        when {
          isOptional && value == optionalValue -> {
            // Write nothing.