get maxConcurrentChunks() {
    if (!process.env.GENERIC_OPEN_AI_EMBEDDING_MAX_CONCURRENT_CHUNKS)
      return 500;
    if (
      isNaN(Number(process.env.GENERIC_OPEN_AI_EMBEDDING_MAX_CONCURRENT_CHUNKS))
    )
      return 500;
    return Number(process.env.GENERIC_OPEN_AI_EMBEDDING_MAX_CONCURRENT_CHUNKS);
  }
returns the `GENERIC_OPEN_AI_EMBEDDING_MAX_CONCURRENT_CHUNKS` env variable as a number
or 500 if the env variable is not set or is not a number.
@returns {number}