Write bench-tps in terms of client (#3904)

* Write bench-tps in terms of client

* Add transactions_addr method for logging

* Move cluster config outside do_bench_tps

* Add BankClient test

sdk/src/client.rs

@@ -16,7 +16,9 @@ use crate::transaction;
 use crate::transport::Result;
 use std::io;
 
-pub trait Client: SyncClient + AsyncClient {}
+pub trait Client: SyncClient + AsyncClient {
+    fn transactions_addr(&self) -> String;
+}
 
 pub trait SyncClient {
     /// Create a transaction from the given message, and send it to the

sdk/src/transport.rs

@@ -1,4 +1,6 @@
 use crate::transaction::TransactionError;
+use std::error;
+use std::fmt;
 use std::io;
 
 #[derive(Debug)]
@@ -7,6 +9,16 @@ pub enum TransportError {
     TransactionError(TransactionError),
 }
 
+impl error::Error for TransportError {}
+impl fmt::Display for TransportError {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            TransportError::IoError(err) => write!(formatter, "{:?}", err),
+            TransportError::TransactionError(err) => write!(formatter, "{:?}", err),
+        }
+    }
+}
+
 impl TransportError {
     pub fn unwrap(&self) -> TransactionError {
         if let TransportError::TransactionError(err) = self {