Trait MapHint 

pub trait MapHint: Sized + Sealed {
    // Required method
    fn get(self) -> Option<usize>;

    // Provided methods
    fn require<C>(self, cx: C) -> Result<usize, C::Error>
       where C: Context { ... }
    fn size_hint(self) -> SizeHint { ... }
}

A size hint passed in when encoding or decoding a map.

Required Methods

fn get(self) -> Option<usize>

Get an optional map hint.

Provided Methods

fn require<C>(self, cx: C) -> Result<usize, C::Error>

where C: Context,

Require a map hint or raise an error indicating that the format doesn’t support maps of unknown size if one is not present.

fn size_hint(self) -> SizeHint

Coerce into a [SizeHint].

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl MapHint for Option<usize>

fn get(self) -> Option<usize>

impl MapHint for usize

fn get(self) -> Option<usize>

fn require<C>(self, _: C) -> Result<usize, C::Error>

where C: Context,

fn size_hint(self) -> SizeHint

Implementors