Keep routing table in MVar.

Since table updates is not atomic operations and may perform IO we should
be able to gain /exclusive/ access to the table. Consider insertNode
function:

1) Thread A read table_1;
2) Thread B read table_1;
3) Thread B ping node Z and it does not respond and get removed;
4) Thread B remove node Z from table_1 and get table_2;
5) Thread B put table_2;
6) Thread A insert a new node and get table_3;
4) Thread A put table_3;

The problem is that final table_3 do have the removed node. At the
moment, exclusive access solves this problem.

0 files changed, 0 insertions, 0 deletions