Struct Snapshot 

struct Snapshot {
    total: CpuTime,
    per_core: Vec<CpuTime>,
    instant: Instant,
    proc_ticks: HashMap<i32, (u64, u64)>,
    proc_io: HashMap<i32, (u64, u64)>,
}

Fields

total: CpuTime

Aggregate across all logical CPUs (the “cpu” summary line in /proc/stat).

per_core: Vec<CpuTime>

Per-logical-CPU entries (cpu0, cpu1, …).

instant: Instant

Wall-clock time of this snapshot, used to normalize process tick deltas.

proc_ticks: HashMap<i32, (u64, u64)>

{ pid -> (utime, stime) } for root process + all descendants. Empty when no PID is being tracked.

proc_io: HashMap<i32, (u64, u64)>

{ pid -> (read_bytes, write_bytes) } from /proc/pid/io. Empty when no PID is tracked or /proc/pid/io is unreadable.