Parse inv messages.

[hdevalence]

We should be able to parse inventory messages.

[hdevalence]

I think this is blocked on #21, because in order to represent the "inventory items" as

/// An inventory item which refers to some advertised or requested data.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
enum InventoryItem {
    Error,
    Tx(TxHash),
    Block(BlockHash),
    FilteredBlock(BlockHash),
}

we need the TxHash, BlockHash types to exist already.

[hdevalence]

@dconnolly can I move the existing InventoryType/InventoryVector structs out of zebra-chain and into zebra-network? I think that they're just used for the network protocol, so it seems like a better home.

[dconnolly]

@dconnolly can I move the existing InventoryType/InventoryVector structs out of zebra-chain and into zebra-network? I think that they're just used for the network protocol, so it seems like a better home.

Yes I think this is correct, Inventory* look like message or general metadata rather than an independent type. 👍

[hdevalence]

Closed by the combination of #31 and #38 (which replaced some stub types).