Removed redundant checks and streamlined the switch-case structure.
Added test cases for both HumanBytes and HumanBytes2 to cover a wide range of scenarios.
This change adds support for multiple concurrent requests, as well as
loading multiple models by spawning multiple runners. The default
settings are currently set at 1 concurrent request per model and only 1
loaded model at a time, but these can be adjusted by setting
OLLAMA_NUM_PARALLEL and OLLAMA_MAX_LOADED_MODELS.