Replace unneeded Function with imperative approach

The latter is more concise, faster, and compact.  .class size in bytes
before:

LocalAsyncBlobStore$5.class      1883
LocalAsyncBlobStore.class       20743

and after:

LocalAsyncBlobStore.class       21041
Merge pull request #1305 from maginatics/unneeded-function-example

Replace unneeded Function with imperative approach