Add poke to state network spec

state/state-network.md

@@ -65,7 +65,18 @@ custom_payload = SSZ.serialize(custom_data)
 
 #### POKE Mechanism
 
-The [POKE Mechanism](./portal-wire-protocol#poke-mechanism) MUST be disabled for the state network. As `content_for_retrieval` is different from `content_for_offer` the POKE mechanism cannot offer content that is verifiable.
+As `content_for_retrieval` is different from `content_for_offer` the POKE mechanism cannot offer content that is verifiable without providing
+the proof/s that are contained in the `content_for_offer` payload. These proofs are usually available when walking down the trie during content
+lookups such as during an `eth_getBalance` JSON-RPC call implemented in the state network.
+
+The [POKE Mechanism](./portal-wire-protocol#poke-mechanism) for the state network requires building a `content_for_offer` by combining the `content_for_retrieval` with the parent proof/s and block hash. This is implemented differently for each
+type of content:
+- For account trie nodes the trie node in the `content_for_retrieval` is appended to the parent account proof and then combined with the block hash to build the `content_for_offer`.
+- For contract trie nodes the trie node in the `content_for_retrieval` is appended to the parent storage proof and then combined with the account proof and block hash to build the `content_for_offer`.
+- For contract code the code in the `content_for_retrieval` is combined with the account proof and block hash to build the `content_for_offer`.
+
+This POKE mechanism as described above SHOULD be executed after looking up content from the network, whenever the proofs and block hash are locally available
+to be used to build the `content_for_offer`.
 
 ### Routing Table
 
@@ -340,7 +351,7 @@ something like this (numbers next to branches indicate the index in the branch n
 
 ```
          branch (root)
-       /0             \1 
+       /0             \1
 prefix: 123            prefix: 234
 value:  A              value:  B
 ```