Function bootstrap_default_memory_manager_with_config 

pub fn bootstrap_default_memory_manager_with_config<P: RuntimeBootstrapPolicy>(
    config: MemoryManagerConfig,
    policy: &P,
) -> Result<CommittedAllocations, RuntimeBootstrapError<P::Error>>

Bootstrap the default runtime with an explicit bucket setting and allocation policy.

The first construction uses this setting; repeated calls and reopened memory must match it exactly before bootstrap effects. Call this during bootstrap before any operation that would construct the default runtime. Use super::GenericRangePolicy to select the built-in policy, or pass the host’s custom policy. This operation does not adopt a different bound policy.