ChannelConfig gives handle to the channel config.

Envelope contains data of the common.Envelope; some byte fields are already unmarshalled to structs and we preserve the unmarshalled version so as to not duplicate the unmarshalling work.

InvalidErr is intended to be used by a ProcessorCreator or a Processor to indicate that the transaction is found to be invalid.

KeyValueItr helps iterates over the results of a range scan query.

State exposes functions that helps a `Processor` in retrieving the latest state The `State` passed to the `Process` function represents the world state for the channel as of commit of the preceding valid transaction in the block.

Processor contains logic for processing a transaction on the committing peer.

ProcessorCreator creates a new instance of a processor of a particular transaction type.

PvtdataSourceHinter is an optional interface that a `Processor` implements to return the peers (identity bytes, e.g., certs) that could be the potential source for the private data associated with the transaction.

ReadHinter is an optional interface that a `Processor` implementation is encouraged to implement if the `Processor` can give any hints about what data items it would potentially read during its processing.

Reprocessor is an optional interface that a `Processor` is encouraged to implement if a significant large number of transactions of the corresponding type are expected to be present and validation of the transaction is significantly resource consuming (e.g., signature matching/crypto operations) as compare to manipulating the state.

ReprocessReadHinter is an optional interface that a `Processor` may choose to implement if it implements Reprocessor.