message: Add new Agent2Agent API for agent.rs.
diff: @@ -8,6 +8,41 @@ use utils::cstring::CStringUtils;
  use self::libc::c_char;
  +#[no_mangle]
  +pub extern fn indy_prep_msg(command_handle: i32,
  + sender_vk: *const c_char,
  + recipient_vk: *const c_char,
  + msg_data: *const u8,
  + msg_len: u32,
  + cb: Option<extern fn(command_handle_: i32,
  + encrypted_msg: *const c_char,
  + encrypted_len: u32)>) -> ErrorCode {
  + unimplemented!();
  +}
  +
  +#[no_mangle]
  +pub extern fn indy_prep_anonymous_msg(command_handle: i32,
  + recipient_vk: *const c_char,
  + msg_data: *const u8,
  + msg_len: u32,
  + cb: Option<extern fn(command_handle_: i32,
  + encrypted_msg: *const c_char,
  + encrypted_len: u32)>) -> ErrorCode {
  + unimplemented!();
  +}
  +
  +#[no_mangle]
  +pub extern fn indy_parse_msg(command_handle: i32,
  + recipient_vk: *const c_char,
  + encrypted_msg: *const u8,
  + encrypted_len: u32,
  + cb: Option<extern fn(command_handle_: i32,
  + sender_vk: *const c_char,
  + msg_data: *const u8,
  + msg_len: u32)>) -> ErrorCode {
  + unimplemented!();
  +}
  +
  /// Establishes agent to agent connection.
  ///
  /// Information about sender Identity must be saved in the wallet with indy_create_and_store_my_did
  