Define an sftraj
new_sftraj(data, group_col, sf_col, time_col, error_col = NA)
data.frame with multi_burst column, geometry column, time_col (integer/POSIXct), and error column (optional)
column name of multi_burst in `data`
column name of geometry in `data`
column name of time in `data`
column name of error in `data`