(PECL solr >= 0.9.2) Checks if the current position internally is still valid

(PECL solr >= 0.9.2) Drops all the fields in the document

(PECL solr >= 0.9.2) Sorts the fields in the document

(PECL solr >= 0.9.2) Creates a copy of a SolrDocument object

(PECL solr >= 0.9.2) Merges source to the current SolrDocument

(PECL solr >= 0.9.2) Used for custom serialization

(PECL solr >= 0.9.2) Returns a SolrInputDocument equivalent of the object

(PECL solr >= 0.9.2) Retrieves the current key

(PECL solr >= 0.9.2) Removes a field from the document

(PECL solr >= 0.9.2) Constructor public S