Enum Durability 

pub enum Durability {
    Fast,
    Atomic,
    Durable,
}

Write-durability strategy for FileStorage.

Variants

Fast

Overwrite the target file in place (open + truncate + write).

Fastest: after a key’s file exists, each save reuses the same inode/MFT entry with no file creation or rename. A crash mid-write leaves a record whose stored checksum no longer matches its data; such a record is detected on load and treated as absent, so the affected task simply re-runs (which fits the executor’s re-run-incomplete-work model).

Atomic

Write to a unique temp file, then atomically rename it over the target.

A crash never destroys the previous good record (you always read either the old or the new value), at the cost of a file create + rename per save. Bytes may still be sitting in the OS page cache, so this protects against process crashes but not necessarily power loss.

Durable

Like Durability::Atomic, but fsyncs the data to physical storage before the rename and best-effort fsyncs the directory afterward.

The strongest guarantee — survives power loss / kernel panic — and the slowest (each save waits on disk flush). The directory sync is a no-op on platforms where it is not available (e.g. Windows, where NTFS journaling makes the rename durable in practice).

Trait Implementations

impl Clone for Durability

fn clone(&self) -> Durability

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Durability

impl Debug for Durability

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Durability

impl PartialEq for Durability

fn eq(&self, other: &Durability) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Durability