message: cc/client/client_session.h: Single-parameter constructor should be marked explicit
diff: @@ -64,7 +64,7 @@ class ClientSession {
  ClientSession(const Scope& scope, const string& target);
  /// Same as above, but use the empty string ("") as the target specification.
  - ClientSession(const Scope& scope);
  + explicit ClientSession(const Scope& scope);
  /// Create a new session, configuring it with `session_options`.
  ClientSession(const Scope& scope, const SessionOptions& session_options);
  