Firestore/src/V1beta1/ListenResponse.php
public function setFilter($var)
    {
        GPBUtil::checkMessage($var, \Google\Cloud\Firestore\V1beta1\ExistenceFilter::class);
        $this->writeOneof(5, $var);

        return $this;
    }
public function setFilter($var)
    {
        GPBUtil::checkMessage($var, \Google\Cloud\Firestore\V1beta1\ExistenceFilter::class);
        $this->writeOneof(5, $var);

        return $this;
    }
public function setFilter ( $ var ) { GPBUtil :: checkMessage ( $ var , \ Google \ Cloud \ Firestore \ V1beta1 \ ExistenceFilter :: class ) ; $ this -> writeOneof ( 5 , $ var ) ; return $ this ; }
A filter to apply to the set of documents previously returned for the
given target.
Returned when documents may have been removed from the given target, but
the exact documents are unknown.

Generated from protobuf field <code>.google.firestore.v1beta1.ExistenceFilter filter = 5;</code>
@param \Google\Cloud\Firestore\V1beta1\ExistenceFilter $var
@return $this
A filter to apply to the set of documents previously returned for the given target . Returned when documents may have been removed from the given target but the exact documents are unknown .