Function validate_token_coverage 

pub fn validate_token_coverage(peers: &[Peer]) -> Result<(), TokenCoverageError>

Validate that every (dc, rack) in peers produces a usable ring under crate::cluster::vnode::dispatch semantics.

The check is per-rack: a fault in DC2 still rejects even if DC1 is fully populated, because the dispatcher walks each rack independently when planning ([collect_routable] pushes one entry per (dc, rack)).

Returns the first fault encountered. The traversal order is the natural BTreeMap order over (dc, rack) strings, which is stable across runs given identical input.

Errors

• TokenCoverageError::EmptyRack if any (dc, rack) contributes zero tokens.
• TokenCoverageError::Overlap if two peers in the same rack claim the same token value.

Examples

use dynomite::cluster::coverage::{validate_token_coverage, TokenCoverageError};
use dynomite::cluster::peer::{Peer, PeerEndpoint};
use dynomite::hashkit::DynToken;

let a = Peer::new(
    0, PeerEndpoint::tcp("a".into(), 8101),
    "r".into(), "d".into(),
    vec![DynToken::from_u32(7)], true, true, false,
);
let b = Peer::new(
    1, PeerEndpoint::tcp("b".into(), 8101),
    "r".into(), "d".into(),
    vec![DynToken::from_u32(7)], false, true, false,
);
assert!(matches!(
    validate_token_coverage(&[a, b]),
    Err(TokenCoverageError::Overlap { .. })
));