code: public boolean trimCurrentThreadCache() {
          PoolThreadCache cache = threadCache.getIfExists();
          if (cache != null) {
              cache.trim();
              return true;
          }
          return false;
      }
docs: Trim thread local cache for the current {@link Thread}, which will give back any cached memory that was not
  allocated frequently since the last trim operation.
  
  Returns {@code true} if a cache for the current {@link Thread} exists and so was trimmed, false otherwise.