Domain.DLSSourceDomain-local Storage
Type of a DLS key
new_key f returns a new key bound to initialiser f for accessing domain-local variables.
If split_from_parent is provided, spawning a domain will derive the child value (for this key) from the parent value.
Note that the split_from_parent call is computed in the parent domain, and is always computed regardless of whether the child domain will use it. If the splitting function is expensive or requires client-side computation, consider using 'a Lazy.t key.
get k returns v if a value v is associated to the key k on the calling domain's domain-local state. Sets k's value with its initialiser and returns it otherwise.