update

        # OpenSSL::Digest.update

(from ruby core)
### Implementation from Digest
---
    digest.update(string) -> aString

---

Not every message digest can be computed in one single pass. If a
message digest is to be computed from several subsequent sources, then
each may be passed individually to the Digest instance.

### Example
    digest = OpenSSL::Digest.new('SHA256')
    digest.update('First input')
    digest << 'Second input' # equivalent to digest.update('Second input')
    result = digest.digest