Unique ID

Data Type	Object	Slice	Vector	Option
Unique identfier (`UniqueID` or `flat_message::UniqueID`)	Yes	-	-	-

Remarks:

A UniqueID is a 64-bit value that must be non-zero and is intended to appear only once in a struct. It serves as a unique identifier for a message. The following example will not compile as it uses two fields with the type UniqueID:

#![allow(unused)]
fn main() {
use flat_message::*;

// code will not compile (two ids)
#[derive(FlatMessage)]
struct Example {
    id1: UniqueID
    id2: UniqueID
}
}

The use of UniqueID is optional—you don't need to include it in your structure unless you want to store messages in a database or require a unique identifier.
Since UniqueID can be used only once per struct, its field name is not stored; it will be automatically mapped to any field with the same type.

Methods

The following methods are available for an UniqueID:

Method	Purpose
`new()`	Creates a new UniqueID instance with a globally unique, non-zero 64-bit value. It uses an atomic counter (GLOBAL_ID) to ensure each call produces a distinct value.
`with_value(value: u64)`	Creates a UniqueID from a manually provided 64-bit value. This method bypasses automatic generation and should be used only when you already have a valid ID.
`value(&self)`	Returns the underlying 64-bit integer value of the UniqueID. Useful for reading or storing the ID in external systems (e.g., databases).

Example

#![allow(unused)]
fn main() {
use flat_message::*;

#[derive(FlatMessage)]
struct Example {
    name: String,
    grade: u32,
    id: UniqueID
}
}