Performance issue with fields > 1 kilobyte about em-mongo

[bcg]

I don't think benchmarking sync and async operations in the same event loop is a great idea, but I don't see why that would be throwing off the results here. My guess at first glance is this is probably a bug.

[tammofreese]

Found it! The problem is in connection.rb:

    if @buffer.more?
      remaining_bytes= @[e-mail]
      @buffer = BSON::ByteBuffer.new(@buffer.to_s[@buffer.position,remaining_bytes])
      @buffer.rewind
    else
      @buffer.clear
    end

If there is more data available, the buffer is always recreated, even if the position in the buffer is 0 and the recreation is not needed. For bigger data, this problem gets worse by n*2. I just pushed a fix and will send you a pull request next.

[dCSeven]

Done with #42