Check client balance and only airdrop if less than TPS quota

src/bin/client-demo.rs

@@ -224,12 +224,15 @@ fn main() {
     let mut client = mk_client(&leader);
 
     let starting_balance = client.poll_get_balance(&id.pubkey()).unwrap();
-
     let txs: i64 = 500_000;
-    println!("Airdropping {:?} tokens", txs);
+
-    let _airdrop = request_airdrop(&drone_addr, &id, txs as u64).unwrap();
+    if starting_balance < txs {
+        let airdrop_amount = txs - starting_balance;
+        println!("Airdropping {:?} tokens", airdrop_amount);
+        let _airdrop = request_airdrop(&drone_addr, &id, airdrop_amount as u64).unwrap();
         // TODO: return airdrop Result from Drone
         sleep(Duration::from_millis(100));
+
         let balance = client.poll_get_balance(&id.pubkey()).unwrap();
         println!("Your balance is: {:?}", balance);
 
@@ -237,6 +240,7 @@ fn main() {
             println!("TPS airdrop limit reached; wait 60sec to retry");
             exit(1);
         }
+    }
 
     println!("Get last ID...");
     let mut last_id = client.get_last_id();