Function svn_stringbuf_from_aprfile 

pub unsafe extern "C" fn svn_stringbuf_from_aprfile(
    result: *mut *mut svn_stringbuf_t,
    file: *mut apr_file_t,
    pool: *mut apr_pool_t,
) -> *mut svn_error_t

Sets @a *result to a string containing the contents of the already opened @a file. Reads from the current position in file to the end. Does not close the file or reset the cursor position.

@note due to memory pseudo-reallocation behavior (due to pools), this can be a memory-intensive operation for large files.