Tests if the stream supports the #GSeekableIface.
Tests if the length of the stream can be adjusted with gio.seekable.Seekable.truncate.
Seeks in the stream by the given offset, modified by type.
Tells the current position within the stream.
Sets the length of the stream to offset. If the stream was previously larger than offset, the extra data is discarded. If the stream was previously shorter than offset, it is extended with NUL ('\0') bytes.
gio.seekable.Seekable is implemented by streams (implementations of gio.input_stream.InputStream or gio.output_stream.OutputStream) that support seeking.
Seekable streams largely fall into two categories: resizable and fixed-size.
gio.seekable.Seekable on fixed-sized streams is approximately the same as POSIX `lseek()` on a block device (for example: attempting to seek past the end of the device is an error). Fixed streams typically cannot be truncated.
gio.seekable.Seekable on resizable streams is approximately the same as POSIX `lseek()` on a normal file. Seeking past the end and writing data will usually cause the stream to resize by introducing zero bytes.