chore: address PR review comments on instance_id

Author: keelerm84

libs/server-sdk/src/instance_id.cpp

@@ -8,9 +8,9 @@ namespace launchdarkly::server_side {
 
 std::string MakeInstanceId() {
     // boost::uuids::random_generator emits a version 4 (random) UUID, which is
-    // what the SCMP spec requires. The generator carries state (an internal
-    // RNG), so constructing it on every call is fine for our use case where we
-    // only call MakeInstanceId once per SDK instance.
+    // what the SCMP spec requires. The generator carries state (an internal RNG
+    // seeded from system entropy on construction), so we cache it per thread to
+    // avoid redundant entropy draws on repeated calls.
     static thread_local boost::uuids::random_generator generator;
     return boost::uuids::to_string(generator());
 }

libs/server-sdk/src/instance_id.hpp

@@ -9,8 +9,6 @@ namespace launchdarkly::server_side {
  * estimating server-connection-minutes when polling. The value is a v4 UUID
  * that is generated once per SDK instance and remains constant for the
  * lifetime of the client.
- *
- * See: sdk-specs / SCMP-server-connection-minutes-polling.
  */
 inline constexpr char const* kInstanceIdHeader = "X-LaunchDarkly-Instance-Id";