This commit exports and renames the following variable names:
- `PendingInput` is now `PendingInputResponse` as it's responding to a
request.
- `pendingInput` is now renamed and exported as `SweeperInput`.
- `pendingInputs` is now renamed and exported as `InputsMap`.
This commit is first made from running:
```
gofmt -d -w -r 'PendingInput -> PendingInputResponse' .
gofmt -d -w -r 'pendingInput -> SweeperInput' .
gofmt -d -w -r 'pendingInputs -> InputsMap' .
```
And followed by some docs and variable names fixes.
This commit adds `BudgetAggregator` as a new implementation of
`UtxoAggregator`. This aggregator will group inputs by their deadline
heights and create input sets that can be used directly by the fee
bumper for fee calculations.
This commit changes how `WithCoinSelectLock` is used - previously the
lock is held when creating the input sets, now it's only be held after
the input sets have been created and explicitly signal they need wallet
inputs.
This commit makes the `ClusterInputs` directly returning the `InputSet`
so the sweeper doesn't know about the existence of `Cluster` interface.
This way we can have a deeper interface as the sweeper only needs to
interact with `Aggregator` only to get the final input sets, leaving the
implementation details being managed by `SimpleAggregator` and future
aggregators.
Previously the fee rate is tracked at cluster level, which may not be
accurate as each cluster is then divided into input sets. And these sets
are what's actually included in the final sweeping tx. To properly
reflect the final fee rate used in the sweeping tx, `InputSet` is added
so more customized clustering logic can be implemented in the future.
For intance, atm it's clustered by fee rates, while we may also cluster
by deadlines, urgencies, etc.
This commit adds a new interface `Cluster` to manage cluster-level
inputs grouping. This new interface replaces the `inputCluster` and will
be futher refactored so the sweeper can use a much smaller coin
selection lock.
This commit refactors the grouping logic into a new interface
`UtxoAggregator`, which makes it easier to write tests and opens
possibility for future customized clustering strategies.
The old clustering logic is kept as and moved into `SimpleAggregator`.
