EncodedPayload Object
  If your exploit supports payloads, it must retrieve the user supplied payload
during exploitation.  The EncodedPayload environment entry is setup by the
Framework before the Exploit method is called on an exploit, allowing the
exploit to retrieve several attributes of the payload.

Payload: Retrieves the entire payload, including nops and encoded payload
EncodedPayload: Retrieves just the encoded payload, no nops
RawPayload: Retrieves the unencoded payload (also no nops)
Nops: Returns just the nop sled
NopsLength: Returns the length of the nop sled, handy for bruteforce stepping