invalidivsacim_est: This is the main function to compute the estimator in C++
In ivsacim: Structural Additive Cumulative Intensity Models with IV

This is the main function to compute the estimator in C++

invalidivsacim_est(
  time,
  event,
  stime,
  Z,
  Z_c,
  D_status,
  D_status_c,
  Z_model_mat,
  eps_1,
  D_model_mat,
  eps_2,
  weights
)

`time`	censored event time
`event`	event indicator
`stime`	unique sorted noncensored event time
`Z`	the instrument
`Z_c`	centered IV
`D_status`	treatment process at each noncensored event time
`D_status_c`	centered treatment process at each noncensored event time
`Z_model_mat`	bread matrix from modeling IV
`eps_1`	influence function from modeling IV
`D_model_mat`	bread matrix from modeling treatment
`eps_2`	influence function from modeling treatment
`weights`	optional weights