哈希函数：MurmurHash

MurmurHash算法

void AsyncLogging::append(const char* logline, int len)
{
  muduo::MutexLockGuard lock(mutex_);
  if (currentBuffer_->avail() > len)
  {
    currentBuffer_->append(logline, len);
  }
  else
  {
    buffers_.push_back(std::move(currentBuffer_));

    if (nextBuffer_)
    {
      currentBuffer_ = std::move(nextBuffer_);
    }
    else
    {
      currentBuffer_.reset(new Buffer); // Rarely happens
    }
    currentBuffer_->append(logline, len);
    cond_.notify();
  }
}