Function btck_block_tree_entry_get_block_header 

pub unsafe extern "C" fn btck_block_tree_entry_get_block_header(
    block_tree_entry: *const btck_BlockTreeEntry,
) -> *mut btck_BlockHeader

@brief Return the btck_BlockHeader associated with this entry.

@param[in] block_tree_entry Non-null. @return btck_BlockHeader.