Insert a new block before the current block. You cannot insert a block
before the first STREAMINFO block. You cannot insert a STREAMINFO block
as there can be only one, the one that already exists at the head when you
read in a chain. The chain takes ownership of the new block and it will be
deleted when the chain is deleted. The iterator will be left pointing to
the new block.
\param iterator A pointer to an existing initialized iterator.
\param block A pointer to a metadata block to insert.
\assert
\code iterator != NULL \endcode
\a iterator has been successfully initialized with
FLAC__metadata_iterator_init()
\retval FLAC__bool
\c false if the conditions in the above description are not met, or
a memory allocation error occurs, otherwise \c true.
Insert a new block before the current block. You cannot insert a block before the first STREAMINFO block. You cannot insert a STREAMINFO block as there can be only one, the one that already exists at the head when you read in a chain. The chain takes ownership of the new block and it will be deleted when the chain is deleted. The iterator will be left pointing to the new block.
\param iterator A pointer to an existing initialized iterator. \param block A pointer to a metadata block to insert. \assert \code iterator != NULL \endcode \a iterator has been successfully initialized with FLAC__metadata_iterator_init() \retval FLAC__bool \c false if the conditions in the above description are not met, or a memory allocation error occurs, otherwise \c true.