@Override
    public boolean equals(Object o) {
        if (o == this) return true;
        if ( ! (o instanceof SearchChainInvocationSpec other)) return false;

        if ( ! Objects.equals(this.searchChainId, other.searchChainId)) return false;
        if ( ! Objects.equals(this.source, other.source)) return false;
        if ( ! Objects.equals(this.provider, other.provider)) return false;
        if ( ! Objects.equals(this.federationOptions, other.federationOptions)) return false;
        if ( ! Objects.equals(this.schemas, other.schemas)) return false;
        return true;
    }
The provider to invoke, or null if none
container-search/src/main/java/com/yahoo/search/federation/sourceref/SearchChainInvocationSpec.java