public String getApiKeyHeader(Query query) {
        return lookupPropertyWithOrWithoutPrefix(API_KEY_HEADER, p -> query.getHttpRequest().getHeader(p));
    }
Base class for LLM searchers. Provides utilities for calling LLMs and handling properties.

@author lesters
container-search/src/main/java/ai/vespa/search/llm/LLMSearcher.java