Function create_runtime_env 

pub fn create_runtime_env(
    pipeline_config: &PipelineConfig,
) -> Result<Arc<RuntimeEnv>, ControllerError>

Build the shared datafusion RuntimeEnv for a pipeline.

Build once per pipeline and share the Arc across every SessionContext. A separate RuntimeEnv per context would give each its own pool, multiplying the effective memory budget by (1 + #connectors).