Add benchmark for listunspent

Closes #2645.

src/wallet/rpcwallet.cpp

@@ -2609,6 +2609,8 @@ UniValue zc_benchmark(const UniValue& params, bool fHelp)
                 throw JSONRPCError(RPC_TYPE_ERROR, "Benchmark must be run in regtest mode");
             }
             sample_times.push_back(benchmark_loadwallet());
+        } else if (benchmarktype == "listunspent") {
+            sample_times.push_back(benchmark_listunspent());
         } else {
             throw JSONRPCError(RPC_TYPE_ERROR, "Invalid benchmarktype");
         }

src/zcbenchmarks.cpp

@@ -465,3 +465,12 @@ double benchmark_loadwallet()
     post_wallet_load();
     return res;
 }
+
+double benchmark_listunspent()
+{
+    UniValue params(UniValue::VARR);
+    struct timeval tv_start;
+    timer_start(tv_start);
+    auto unspent = listunspent(params, false);
+    return timer_stop(tv_start);
+}

src/zcbenchmarks.h

@@ -18,5 +18,6 @@ extern double benchmark_increment_note_witnesses(size_t nTxs);
 extern double benchmark_connectblock_slow();
 extern double benchmark_sendtoaddress(CAmount amount);
 extern double benchmark_loadwallet();
+extern double benchmark_listunspent();
 
 #endif