usechrono::prelude::*;useserde::{Deserialize, Serialize};/// Echo message contains a string payload, and a timestamp at which the message was constructed.
/// The `Serialize` and `Deserialize` traits allow for serialization by the `serde` crate.
#[derive(PartialEq, Clone, Serialize, Deserialize, Debug)]pubstructEchoMsg{pubpayload: String,
pubts:DateTime<Utc>,
}