Remove using namespace declarations at namespace scope in headers

src/test/csf/Peer.h

@@ -393,8 +393,6 @@ struct Peer
     Ledger const*
     acquireLedger(Ledger::ID const& ledgerID)
     {
-        using namespace std::chrono;
-
         auto it = ledgers.find(ledgerID);
         if (it != ledgers.end())
             return &(it->second);
@@ -411,7 +409,7 @@ struct Peer
                 return nullptr;
         }
 
-
+        using namespace std::chrono_literals;
         SimDuration minDuration{10s};
         for (auto const& link : net.links(this))
         {
@@ -457,6 +455,7 @@ struct Peer
                 return nullptr;
         }
 
+        using namespace std::chrono_literals;
         SimDuration minDuration{10s};
         for (auto const& link : net.links(this))
         {

src/test/csf/impl/ledgers.cpp

@@ -101,6 +101,7 @@ LedgerOracle::accept(
     NetClock::duration closeTimeResolution,
     NetClock::time_point const& consensusCloseTime)
 {
+    using namespace std::chrono_literals;
     Ledger::Instance next(*parent.instance_);
     next.txs.insert(txs.begin(), txs.end());
     next.seq = parent.seq() + Ledger::Seq{1};

src/test/csf/timers.h

@@ -45,12 +45,12 @@ class HeartbeatTimer
 
 public:
     HeartbeatTimer(
-            Scheduler& sched,
-            SimDuration interval = std::chrono::seconds(60s),
-            std::ostream& out = std::cerr)
-            : scheduler_{sched}, interval_{interval}, out_{out},
-              startRealTime_{RealClock::now()},
-              startSimTime_{sched.now()}
+        Scheduler& sched,
+        SimDuration interval = std::chrono::seconds {60},
+        std::ostream& out = std::cerr)
+        : scheduler_{sched}, interval_{interval}, out_{out},
+          startRealTime_{RealClock::now()},
+          startSimTime_{sched.now()}
     {
     }