Build a message
@param{Keychain} keychain used to send transaction to BC
@param{ApiService} API with blockchain
@param{String} Smart contract's address
@param{String} Content of the message (no encrypt)
@param{String} Address of the member who want to send message
@param{String} Service name in the current keychain (= sender)
@param{KeyPair} Keypair of the sender
Get a discussion from an address
@param{ApiService} API with blockchain
@param{String} Smart contract's address
@param{KeyPair} Keypair of the requester to check if discussion's content can be decrypted
Get the last properties of a discussion
@param{ApiService} API with blockchain
@param{String} Smart contract's address
@param{KeyPair} Keypair of the requester to check if discussion's properties can be decrypted
Read messages in existing discussion
@param{ApiService} API with blockchain
@param{String} Smart contract's address
@param{KeyPair} Keypair of the reader
@param{limit}
@param{pagingOffset}
Send messages in existing discussion
@param{Keychain} keychain used to send transaction to BC
@param{ApiService} API with blockchain
@param{String} Smart contract's address
@param{String} Content of the message (no encrypt)
@param{String} Address of the member who want to send message
@param{String} Service name in the current keychain (= sender)
@param{KeyPair} Keypair of the sender
Update an existing discussion
@param{Keychain} keychain used to send transaction to BC
@param{ApiService} API with blockchain
@param{String} Smart contract's address
@param{List