Commands class implements EPiServer.Find.Api.ICommands interface and all implemented methods are virtual except few ones:

public class Commands : ICommands
{
    // Fields
    private ICache cache;
    private IJsonRequestFactory jsonRequestFactory;
    private Func serializerFactoryMethod;

    // Methods
    public Commands(string serverUrl, IJsonRequestFactory jsonRequestFactory, Func serializerFactoryMethod, ICache cache);
    public virtual BulkCommand Bulk(IEnumerable actions);
    public virtual CountCommand Count(SearchRequestBody searchRequestBody);
    public virtual CreateIndexCommand CreateIndex(string indexName);
    public virtual CreateIndexCommand CreateIndex(string indexName, CreateIndexBody requestBody);
    public virtual DeleteCommand Delete(string index, string type, string id);
    public virtual DeleteByQueryCommand DeleteByQuery();
    public DeleteIndexCommand DeleteIndex(string indexName);
    public virtual GetCommand Get(string index, string type, string id);
    private CommandContext GetCommandContext();
    public virtual IndexCommand Index(string index, string type, object document);
    public IndicesExistsCommand IndicesExists(string indexName);
    public virtual MultiGetCommand MultiGet(IndexName indexName, IEnumerable idAndTypes);
    public MultiSearchCommand MultiSearch();
    public virtual PutMappingCommand PutMapping(TypeMapping typeMapping);
    public virtual SearchCommand Search();
    public virtual UpdateCommand Update(IndexName index, TypeName type, DocumentId id);

    // Properties
    public string ServerUrl { get; private set; }
}

 

What is the reason to make for example

 public MultiSearchCommand MultiSearch();

method non-virtual?

I'm interesting due to the fact that I have to implement some custom "intercept" logic, use custom implementation of some commands (override Commands class methods) and left other unchanged.