src/Observable.php
public function distinct(callable $comparer = null): Observable
    {
        return $this->lift(function () use ($comparer) {
            return new DistinctOperator(null, $comparer);
        });
    }
public function distinct(callable $comparer = null): Observable
    {
        return $this->lift(function () use ($comparer) {
            return new DistinctOperator(null, $comparer);
        });
    }
public function distinct ( callable $ comparer = null ) : Observable { return $ this -> lift ( function ( ) use ( $ comparer ) { return new DistinctOperator ( null , $ comparer ) ; } ) ; }
Returns an observable sequence that contains only distinct elements according to the keySelector and the
comparer. Usage of this operator should be considered carefully due to the maintenance of an internal lookup
structure which can grow large.

@param callable|null $comparer
@return Observable

@demo distinct/distinct.php
@operator
@reactivex distinct
Returns an observable sequence that contains only distinct elements according to the keySelector and the comparer . Usage of this operator should be considered carefully due to the maintenance of an internal lookup structure which can grow large .