code: public com.squareup.okhttp.Call postFleetsFleetIdMembersAsync(Long fleetId, String datasource, String token,
              FleetInvitation fleetInvitation, final ApiCallback<Void> callback) throws ApiException {
  
          com.squareup.okhttp.Call call = postFleetsFleetIdMembersValidateBeforeCall(fleetId, datasource, token,
                  fleetInvitation, callback);
          apiClient.executeAsync(call, callback);
          return call;
      }
docs: Create fleet invitation (asynchronously) Invite a character into the
  fleet. If a character has a CSPA charge set it is not possible to invite
  them to the fleet using ESI --- SSO Scope: esi-fleets.write_fleet.v1
  
  @param fleetId
  ID for a fleet (required)
  @param datasource
  The server name you would like data from (optional, default to
  tranquility)
  @param token
  Access token to use if unable to set a header (optional)
  @param fleetInvitation
  (optional)
  @param callback
  The callback to be executed when the API call finishes
  @return The request call
  @throws ApiException
  If fail to process the API call, e.g. serializing the request
  body object