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//! Utilities.
//!
//! Contains everything which doesn't has a better place
//! to be put in.
use std::marker::Send;
use std::fmt::Debug;

use chrono;
use futures::Future;


/// Type alias for an boxed future which is Send + 'static.
pub type SendBoxFuture<I, E> = Box<Future<Item=I, Error=E> + Send + 'static>;

/// Returns the current data time.
pub fn now() -> chrono::DateTime<chrono::Utc> {
    chrono::Utc::now()
}

/// Trait to allow const `bool` values in generics.
pub trait ConstSwitch: Debug + Copy + Send + Sync + 'static {
    const ENABLED: bool;
}

/// Struct implementing `ConstSwitch` with `ENABLED = true`.
#[derive(Debug, Copy, Clone)]
pub struct Enabled;
impl ConstSwitch for Enabled { const ENABLED: bool = true; }
/// Struct implementing `ConstSwitch` with `ENABLED = false`.
#[derive(Debug, Copy, Clone)]
pub struct Disabled;
impl ConstSwitch for Disabled { const ENABLED: bool = false; }