Struct Instant

pub struct Instant {
    std: Instant,
}
Expand description

A measurement of a monotonically nondecreasing clock. Opaque and useful only with Duration.

Instants are always guaranteed to be no less than any previously measured instant when created, and are often useful for tasks such as measuring benchmarks or timing how long an operation takes.

Note, however, that instants are not guaranteed to be steady. In other words, each tick of the underlying clock may not be the same length (e.g. some seconds may be longer than others). An instant may jump forwards or experience time dilation (slow down or speed up), but it will never go backwards.

Instants are opaque types that can only be compared to one another. There is no method to get “the number of seconds” from an instant. Instead, it only allows measuring the duration between two instants (or comparing two instants).

The size of an Instant struct may vary depending on the target operating system.

§Note

This type wraps the inner std variant and is used to align the Tokio clock for uses of now(). This can be useful for testing where you can take advantage of time::pause() and time::advance().

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§std: Instant

Implementations§

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impl Instant

pub fn now() -> Instant

Returns an instant corresponding to “now”.

§Examples
use tokio::time::Instant;

let now = Instant::now();

pub fn from_std(std: Instant) -> Instant

Create a tokio::time::Instant from a std::time::Instant.

pub fn into_std(self) -> Instant

Convert the value into a std::time::Instant.

pub fn duration_since(&self, earlier: Instant) -> Duration

Returns the amount of time elapsed from another instant to this one, or zero duration if that instant is later than this one.

pub fn checked_duration_since(&self, earlier: Instant) -> Option<Duration>

Returns the amount of time elapsed from another instant to this one, or None if that instant is later than this one.

§Examples
use tokio::time::{Duration, Instant, sleep};

#[tokio::main]
async fn main() {
    let now = Instant::now();
    sleep(Duration::new(1, 0)).await;
    let new_now = Instant::now();
    println!("{:?}", new_now.checked_duration_since(now));
    println!("{:?}", now.checked_duration_since(new_now)); // None
}

pub fn saturating_duration_since(&self, earlier: Instant) -> Duration

Returns the amount of time elapsed from another instant to this one, or zero duration if that instant is later than this one.

§Examples
use tokio::time::{Duration, Instant, sleep};

#[tokio::main]
async fn main() {
    let now = Instant::now();
    sleep(Duration::new(1, 0)).await;
    let new_now = Instant::now();
    println!("{:?}", new_now.saturating_duration_since(now));
    println!("{:?}", now.saturating_duration_since(new_now)); // 0ns
}

pub fn elapsed(&self) -> Duration

Returns the amount of time elapsed since this instant was created, or zero duration if this instant is in the future.

§Examples
use tokio::time::{Duration, Instant, sleep};

#[tokio::main]
async fn main() {
    let instant = Instant::now();
    let three_secs = Duration::from_secs(3);
    sleep(three_secs).await;
    assert!(instant.elapsed() >= three_secs);
}

pub fn checked_add(&self, duration: Duration) -> Option<Instant>

Returns Some(t) where t is the time self + duration if t can be represented as Instant (which means it’s inside the bounds of the underlying data structure), None otherwise.

pub fn checked_sub(&self, duration: Duration) -> Option<Instant>

Returns Some(t) where t is the time self - duration if t can be represented as Instant (which means it’s inside the bounds of the underlying data structure), None otherwise.

Trait Implementations§

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impl Add<Duration> for Instant

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type Output = Instant

The resulting type after applying the + operator.
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fn add(self, other: Duration) -> Instant

Performs the + operation. Read more
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impl AddAssign<Duration> for Instant

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fn add_assign(&mut self, rhs: Duration)

Performs the += operation. Read more
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impl Clone for Instant

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fn clone(&self) -> Instant

Returns a duplicate of the value. Read more
1.0.0 · Source§

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

Performs copy-assignment from source. Read more
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impl Debug for Instant

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

Formats the value using the given formatter. Read more
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impl From<Instant> for Instant

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fn from(time: Instant) -> Instant

Converts to this type from the input type.
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impl Hash for Instant

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fn hash<__H>(&self, state: &mut __H)
where __H: Hasher,

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl Ord for Instant

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fn cmp(&self, other: &Instant) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · Source§

fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized,

Restrict a value to a certain interval. Read more
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impl PartialEq for Instant

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

Tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

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

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fn partial_cmp(&self, other: &Instant) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl Sub<Duration> for Instant

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type Output = Instant

The resulting type after applying the - operator.
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fn sub(self, rhs: Duration) -> Instant

Performs the - operation. Read more
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impl Sub for Instant

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type Output = Duration

The resulting type after applying the - operator.
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fn sub(self, rhs: Instant) -> Duration

Performs the - operation. Read more
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impl SubAssign<Duration> for Instant

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fn sub_assign(&mut self, rhs: Duration)

Performs the -= operation. Read more
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impl Copy for Instant

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impl Eq for Instant

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impl StructuralPartialEq for Instant

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impl<T> Any for T
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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<Q, K> Comparable<K> for Q
where Q: Ord + ?Sized, K: Borrow<Q> + ?Sized,

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fn compare(&self, key: &K) -> Ordering

Compare self to key and return their ordering.
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Converts self into T using Into<T>. Read more
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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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impl<T> FmtForward for T

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fn fmt_binary(self) -> FmtBinary<Self>
where Self: Binary,

Causes self to use its Binary implementation when Debug-formatted.
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fn fmt_display(self) -> FmtDisplay<Self>
where Self: Display,

Causes self to use its Display implementation when Debug-formatted.
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fn fmt_lower_exp(self) -> FmtLowerExp<Self>
where Self: LowerExp,

Causes self to use its LowerExp implementation when Debug-formatted.
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fn fmt_lower_hex(self) -> FmtLowerHex<Self>
where Self: LowerHex,

Causes self to use its LowerHex implementation when Debug-formatted.
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fn fmt_octal(self) -> FmtOctal<Self>
where Self: Octal,

Causes self to use its Octal implementation when Debug-formatted.
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fn fmt_pointer(self) -> FmtPointer<Self>
where Self: Pointer,

Causes self to use its Pointer implementation when Debug-formatted.
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fn fmt_upper_exp(self) -> FmtUpperExp<Self>
where Self: UpperExp,

Causes self to use its UpperExp implementation when Debug-formatted.
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fn fmt_upper_hex(self) -> FmtUpperHex<Self>
where Self: UpperHex,

Causes self to use its UpperHex implementation when Debug-formatted.
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fn fmt_list(self) -> FmtList<Self>
where &'a Self: for<'a> IntoIterator,

Formats each item in a sequence. Read more
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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FromRef<T> for T
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fn from_ref(input: &T) -> T

Converts to this type from a reference to the input type.
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Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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Wrap the input message T in a tonic::Request
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