Add a separate struct that holds a bandwidth information

common-api/src/api.rs

 use crate::crypto::prelude::*;
+use borsh::{BorshDeserialize, BorshSerialize};
 use near_account_id::AccountId;
 use serde::{Deserialize, Serialize};
 use std::{collections::HashSet, time::Duration};
     pub account_id: AccountId,
 }
 
-#[derive(Clone, Debug, Serialize, Deserialize)]
+#[derive(Clone, Debug, Serialize, Deserialize, BorshSerialize, BorshDeserialize)]
+pub struct Bandwidth {
+    pub speed: u32,
+    pub units: String,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize, BorshSerialize, BorshDeserialize)]
 pub struct NodeInfo {
     pub region: String,
-    pub bandwidth: String,
+    pub bandwidth: Bandwidth,
     pub account_id: AccountId,
 }