Optional
Defaults to EMBEDDING_DIMENSIONS, then EMBEDDING_DIMENSIONS.
EMBEDDING_DIMENSIONS
Defaults to EMBEDDING_MODEL, then DEFAULT_EMBEDDING_MODEL.
EMBEDDING_MODEL
Called as batches complete, for a caller with somewhere to show it.
Defaults to OpenAI with OPENAI_API_KEY.
OPENAI_API_KEY
Defaults to
EMBEDDING_DIMENSIONS, then EMBEDDING_DIMENSIONS.