message: macro for naming counter
  Summary: Changed the `DEFINE_counter` macro to accept a second argument for the name of the counter, instead of just using the variable name.
diff: @@ -608,7 +608,12 @@ class StatWrapperBase {
  class CounterWrapper
  : public StatWrapperBase<ThreadCachedServiceData::TLCounter> {
  public:
  + // Two constructors are provided for use in the DEFINE_counter macro below.
  + // If no name is provided, then first constructor is used with the variable
  + // name being the key. If a name is provided, the second constructor is used.
  explicit CounterWrapper(const std::string& key) : StatWrapperBase(key) {}
  + CounterWrapper(const std::string& /*var*/, const std::string& key)
  + : StatWrapperBase(key) {}
  void incrementValue(CounterType amount = 1) {
  tcStat()->incrementValue(amount);
  @@ -1123,8 +1128,8 @@ inline fb303::ThreadCachedServiceData& tcData() {
  #define DECLARE_dynamic_histogram(varname, keyNumArgs) \
  extern ::facebook::fb303::DynamicHistogramWrapper<keyNumArgs> STATS_##varname
  -#define DEFINE_counter(varname) \
  - ::facebook::fb303::CounterWrapper STATS_##varname(#varname)
  +#define DEFINE_counter(varname, ...) \
  + ::facebook::fb303::CounterWrapper STATS_##varname(#varname, ##__VA_ARGS__)
  #define DEFINE_timeseries(varname, ...) \
  ::facebook::fb303::TimeseriesWrapper STATS_##varname(#varname, ##__VA_ARGS__)
  