Are random writes optimized sequentially by Linux kernel?

Hello.

Suppose I perform 1000 RANDOM writes into a file. These writes are saved into Linux writeback buffer and are flushed to the disc asynchronously, that's OK.

The question is: will physical writes be performed later in the sequence of physical SECTOR position on the disc (minimizing head seeking)? Or Linux background writer knows nothing about physical on-disc placement and flushes data in order it is saved in the RAM?

E.g., if I write in the application:

a) block 835
b) block 136
c) block 956
d) block 549
e) block 942

dows the Linux background writer save flush them e.g. in physical order "136 - 549 - 835 - 942 - 956" or not?