0L -> -1L // No more bytes in this part.
            else -> source.read(sink, limit)
          }
        }

        error("unreachable") // TODO(jwilson): fix intersectWith() to return T.
      }

      override fun timeout(): Timeout = timeout
    }

    /**
     * Returns a value in [0..maxByteCount] with the number of bytes that can be read from [source] in