Use Buffer.from('text') rather than new Buffer('text') when available (#778)
Use Buffer.from('text') rather than new Buffer('text') when available (#778)

Fix (node:11826) [DEP0005] DeprecationWarning:
Buffer() is deprecated due to security and usability issues.
Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.

Also, includes a check for whether Buffer.from is actually available:
We check Buffer.alloc rather than Buffer.from because we don't want the base class Uint8Array.from
nodejs/nan,nodejs/nan,nodejs/nan,nodejs/nan