Merge #18638: net: Use mockable time for ping/pong, add tests

fa3365430c5fb57d7c0b5f2bce9fbbe290be93c3 net: Use mockable time for ping/pong, add tests (MarcoFalke)
faab4aaf2fa1153c6d76efc8113fa01b06943ece util: Add count_microseconds helper (MarcoFalke)

Pull request description:

  Switch `CNode::m_ping_start` and `CNetMessage::m_time` to mockable time, so that tests can be added.

  Mockable time is also type-safe, since it uses `std::chrono`

ACKs for top commit:
  jonatack:
    Code review re-ACK fa33654 re-read code, verified rebase per `git range-diff 4b5c919 fa94d6f fa33654`, previous tested ACKs still valid
  troygiorshev:
    ACK fa3365430c5fb57d7c0b5f2bce9fbbe290be93c3

Tree-SHA512: 7d632bd6019ce7c882029e71b667a61517e783af82755a85dd979ef09380934e172dec8b8f91d57b200a30a6e096aeaf01f19fee7f3aed0e0e871c72eb44d70e

1 files changed, 7 insertions, 2 deletions

diff --git a/src/util/time.h b/src/util/time.h
index b00c25f67c..af934e423b 100644
--- a/src/util/time.h
+++ b/src/util/time.h
@@ -15,10 +15,15 @@ void UninterruptibleSleep(const std::chrono::microseconds& n);
 /**
  * Helper to count the seconds of a duration.
  *
- * All durations should be using std::chrono and calling this should generally be avoided in code. Though, it is still
- * preferred to an inline t.count() to protect against a reliance on the exact type of t.
+ * All durations should be using std::chrono and calling this should generally
+ * be avoided in code. Though, it is still preferred to an inline t.count() to
+ * protect against a reliance on the exact type of t.
+ *
+ * This helper is used to convert durations before passing them over an
+ * interface that doesn't support std::chrono (e.g. RPC, debug log, or the GUI)
  */
 inline int64_t count_seconds(std::chrono::seconds t) { return t.count(); }
+inline int64_t count_microseconds(std::chrono::microseconds t) { return t.count(); }
 
 /**
  * DEPRECATED