Implement Sharded TxPool

[terencechain]

We'll need to design and implement a sharding specific transaction pool. One prominent use case of the transaction pool is for the proposer to insert fake transactions. P2P implementation may want to use the receiving of test transactions in the transaction pool. This issue will have impact to proposer implementation as opened in #111

Some questions to answer:
What are the use cases?
How will it work?
Why is it necessary rather than a global TxPool with geth’s current implementation?

[rauljordan]

Hey @terenc3t this is a duplicate of #153

[terencechain]

Ah! My bad

[prestonvanloon]

I don't think this is a duplicate of #153.

#153 outlines the work to create a service to broadcast "fake" transactions through the same mechanism that the P2P library would be broadcasting them within the application. In other words, #153 is supposed to be a stub for P2P that provides a stream of transactions for the proposer to use for development and testing.

It is then up to the proposer to decide where to put these transactions. It would likely be a transaction pool so that is why we have this issue.

[rauljordan]

This should be very minimal for Ruby release and probably piggyback off #171. We want the simplest thing possible and it probably shouldn't do much more than what #171 already does.

[terencechain]

I have written this tx pool design doc but it might be an over kill for Ruby release
https://docs.google.com/document/d/1Arh-7L61nt_iR8REOjrmzMKyu1ZxvzovZ3qOLdmxKRo/edit#

Let's strip it down and come back with a simpler design

[nisdas]

Should we close this ? we do not really know right now what shards would look like and how a txpool would be used in a shard

[terencechain]

This is still a very valid issue and can be implemented anytime. Proposer needs a txpool to store tx, it doesn't have to do with shards, it's just a priority queue. This is up to the client team to design

[terencechain]

Let's close this in favor of a new one when ethereum/consensus-specs#90 gets finalized