## Issue Addressed

The current `lcli` block packing code has an off-by-one where it would include an extra slot (the oldest slot) of attestations as "available" (this means there would be 33 slots of "available" attestations instead of 32).
There is typically only single-digit attestations remaining from that slot and as such does not cause a significant change to the results although every efficiency will have been very slightly under-reported.

## Proposed Changes

Prune the `available_attestation_set` before writing out the data instead of after.

## Additional Info

This `lcli` code will soon be deprecated by a Lighthouse API (#2879)  which will run significantly faster and will be used to hook into our upcoming monitoring platform #2873.

## Issue Addressed
N/A

## Proposed Changes
Add a HTTP API which can be used to compute the block packing data for all blocks over a discrete range of epochs.

## Usage
### Request
```
curl "http:localhost:5052/lighthouse/analysis/block_packing_efficiency?start_epoch=57730&end_epoch=57732"
```
### Response
```
[
  {
    "slot": "1847360",
    "block_hash": "0xa7dc230659802df2f99ea3798faede2e75942bb5735d56e6bfdc2df335dcd61f",
    "proposer_info": {
      "validator_index": 1686,
      "graffiti": ""
    },
    "available_attestations": 7096,
    "included_attestations": 6459,
    "prior_skip_slots": 0
  },
  ...
]
```
## Additional Info

This is notably different to the existing lcli code:
- Uses `BlockReplayer` #2863 and as such runs significantly faster than the previous method.
- Corrects the off-by-one #2878
- Removes the `offline` validators component. This was only a "best guess" and simply was used as a way to determine an estimate of the "true" packing efficiency and was generally not helpful in terms of direct comparisons between different packing methods. As such it has been removed from the API and any future estimates of "offline" validators would be better suited in a separate/more targeted API or as part of 'beacon watch': #2873 
- Includes `prior_skip_slots`.

## Issue Addressed
N/A

## Proposed Changes
Add a HTTP API which can be used to compute the block packing data for all blocks over a discrete range of epochs.

## Usage
### Request
```
curl "http:localhost:5052/lighthouse/analysis/block_packing_efficiency?start_epoch=57730&end_epoch=57732"
```
### Response
```
[
  {
    "slot": "1847360",
    "block_hash": "0xa7dc230659802df2f99ea3798faede2e75942bb5735d56e6bfdc2df335dcd61f",
    "proposer_info": {
      "validator_index": 1686,
      "graffiti": ""
    },
    "available_attestations": 7096,
    "included_attestations": 6459,
    "prior_skip_slots": 0
  },
  ...
]
```
## Additional Info

This is notably different to the existing lcli code:
- Uses `BlockReplayer` #2863 and as such runs significantly faster than the previous method.
- Corrects the off-by-one #2878
- Removes the `offline` validators component. This was only a "best guess" and simply was used as a way to determine an estimate of the "true" packing efficiency and was generally not helpful in terms of direct comparisons between different packing methods. As such it has been removed from the API and any future estimates of "offline" validators would be better suited in a separate/more targeted API or as part of 'beacon watch': #2873 
- Includes `prior_skip_slots`.

## Issue Addressed
N/A

## Proposed Changes
Add a HTTP API which can be used to compute the block packing data for all blocks over a discrete range of epochs.

## Usage
### Request
```
curl "http:localhost:5052/lighthouse/analysis/block_packing_efficiency?start_epoch=57730&end_epoch=57732"
```
### Response
```
[
  {
    "slot": "1847360",
    "block_hash": "0xa7dc230659802df2f99ea3798faede2e75942bb5735d56e6bfdc2df335dcd61f",
    "proposer_info": {
      "validator_index": 1686,
      "graffiti": ""
    },
    "available_attestations": 7096,
    "included_attestations": 6459,
    "prior_skip_slots": 0
  },
  ...
]
```
## Additional Info

This is notably different to the existing lcli code:
- Uses `BlockReplayer` #2863 and as such runs significantly faster than the previous method.
- Corrects the off-by-one #2878
- Removes the `offline` validators component. This was only a "best guess" and simply was used as a way to determine an estimate of the "true" packing efficiency and was generally not helpful in terms of direct comparisons between different packing methods. As such it has been removed from the API and any future estimates of "offline" validators would be better suited in a separate/more targeted API or as part of 'beacon watch': #2873 
- Includes `prior_skip_slots`.

## Issue Addressed
N/A

## Proposed Changes
Add a HTTP API which can be used to compute the block packing data for all blocks over a discrete range of epochs.

## Usage
### Request
```
curl "http:localhost:5052/lighthouse/analysis/block_packing_efficiency?start_epoch=57730&end_epoch=57732"
```
### Response
```
[
  {
    "slot": "1847360",
    "block_hash": "0xa7dc230659802df2f99ea3798faede2e75942bb5735d56e6bfdc2df335dcd61f",
    "proposer_info": {
      "validator_index": 1686,
      "graffiti": ""
    },
    "available_attestations": 7096,
    "included_attestations": 6459,
    "prior_skip_slots": 0
  },
  ...
]
```
## Additional Info

This is notably different to the existing lcli code:
- Uses `BlockReplayer` #2863 and as such runs significantly faster than the previous method.
- Corrects the off-by-one #2878
- Removes the `offline` validators component. This was only a "best guess" and simply was used as a way to determine an estimate of the "true" packing efficiency and was generally not helpful in terms of direct comparisons between different packing methods. As such it has been removed from the API and any future estimates of "offline" validators would be better suited in a separate/more targeted API or as part of 'beacon watch': #2873 
- Includes `prior_skip_slots`.

## Proposed Changes

Remove the `lcli` code which performs block packing analysis.
The `lcli` code has been deprecated by a more performant version available in the HTTP API added in #2879.

## Additional Info

Any applications depending on the `lcli` code should migrate to the version in the HTTP API.
The only feature which is unavailable in the API version is an estimate of live/dead validators. This was originally used to determine a closer approximation of block packing efficiencies since offline validators have a disproportionate impact on efficiencies. However the implimentation in `lcli` is a poor approximation which cannot account for a multitude of factors. It is recommended to simply calculate relative efficiencies instead or use a more advanced method of determining live/dead validators.