ENH: Support bulk requests and snmpset

[aztec102]

Proposed new feature or change:

Good afternoon
Are there plans to add bulk queries and set queries?

[dvolodin7]

Bulk queries are supported for SNMPv3/v3.

While SET queries have an architectural issue. The python data types do not pair with ASN.1 data types and the mapping is not trivial. So we need a robust API to specify data types properly and this API must be consistent with queries.