rem: return;
add: num_requests++; if (num_requests >= request_queue) return;
context: 	void request_a_block(torrent& t, peer_connection& c)	{		piece_picker& p = t.picker();		std::vector<piece_block> interesting_pieces;		interesting_pieces.reserve(100);		p.pick_pieces(c.get_bitfield(), interesting_pieces);		// this vector is filled with the interestin pieces		// that some other peer is currently downloading		// we should then compare this peer's download speed		// with the other's, to see if we should abort another		// peer_connection in favour of this one		std::vector<piece_block> busy_pieces;		busy_pieces.reserve(10);		for (std::vector<piece_block>::iterator i = interesting_pieces.begin();			i != interesting_pieces.end();			++i)		{			if (p.is_downloading(*i))			{				busy_pieces.push_back(*i);				continue;			}			// ok, we found a piece that's not being downloaded			// by somebody else. request it from this peer			c.request_block(*i);			return;		}		// TODO: compare this peer's bandwidth against the		// ones downloading these pieces (busy_pieces)	}