Add repair server dynamometer

[jmpesp]

Here's an example usage on dogfood, measuring a region snapshot's downstairs on another sled:

# /tmp/jwm-downstairs repair-dynamometer \
    --clone-source '[fd00:1122:3344:107::c]:23009'

using http://[fd00:1122:3344:107::c]:23009
The source RegionDefinition is: RegionDefinition { block_size: 512,
extent_size: Block { value: 131072, shift: 9 }, extent_count: 16, uuid:
31fb7fa7-0432-409e-8bec-571b6613b188, encrypted: true,
database_read_version: 1, database_write_version: 1 }
The source mode is: true
Repair extent 0
eid:0 Found repair files: ["000", "000.db", "000.db-shm", "000.db-wal"]
Repair extent 1
eid:1 Found repair files: ["001", "001.db", "001.db-shm", "001.db-wal"]
Repair extent 2
eid:2 Found repair files: ["002", "002.db", "002.db-shm", "002.db-wal"]
Repair extent 3
eid:3 Found repair files: ["003", "003.db", "003.db-shm", "003.db-wal"]
bytes per second: 222755540
Repair extent 4
eid:4 Found repair files: ["004", "004.db", "004.db-shm", "004.db-wal"]
Repair extent 5
eid:5 Found repair files: ["005", "005.db", "005.db-shm", "005.db-wal"]
Repair extent 6
eid:6 Found repair files: ["006", "006.db", "006.db-shm", "006.db-wal"]
bytes per second: 224481150
Repair extent 7
eid:7 Found repair files: ["007", "007.db", "007.db-shm", "007.db-wal"]
Repair extent 8
eid:8 Found repair files: ["008", "008.db", "008.db-shm", "008.db-wal"]
Repair extent 9
eid:9 Found repair files: ["009", "009.db", "009.db-shm", "009.db-wal"]
Repair extent 10
eid:10 Found repair files: ["00A", "00A.db", "00A.db-shm", "00A.db-wal"]
bytes per second: 227660750
Repair extent 11
eid:11 Found repair files: ["00B", "00B.db", "00B.db-shm", "00B.db-wal"]
Repair extent 12
eid:12 Found repair files: ["00C", "00C.db", "00C.db-shm", "00C.db-wal"]
Repair extent 13
eid:13 Found repair files: ["00D", "00D.db", "00D.db-shm", "00D.db-wal"]
bytes per second: 228354910
Repair extent 14
eid:14 Found repair files: ["00E", "00E.db", "00E.db-shm", "00E.db-wal"]
Repair extent 15
eid:15 Found repair files: ["00F", "00F.db", "00F.db-shm", "00F.db-wal"]
B/s: [222755540.0, 224481150.0, 227660750.0, 228354910.0]
B/S mean 225813090 stddev 2645588
B/s min 222755540 max 228354910

Bytes per second looks like about 215.4 MiB/s here.

[leftwo]

This will stream the contents from a running (read-only) downstairs to.. where exactly?
Just into internal buffers which we then discard, right?

[jmpesp]

Yeah, this doesn't do anything with the bytes except count them.