如何在dplyr的跨函数中将函数参数粘合到.names？

library(dplyr)

# 示例数据框
df <- data.frame(
  A = c(1, 2, 3),
  B = c(4, 5, 6),
  C = c(7, 8, 9)
)

# 使用across()函数计算均值和标准差，并自定义列名
result <- df %>%
  mutate(
    across(
      .cols = where(is.numeric),
      .fns = list(mean = mean, sd = sd),
      .names = "{.col}_{fn}"
    )
  )

print(result)

   A B C     A_mean     A_sd     B_mean     B_sd     C_mean     C_sd
1  1 4 7 2.000000 1.000000 5.000000 1.000000 8.000000 1.000000
2  2 5 8 2.000000 1.000000 5.000000 1.000000 8.000000 1.000000
3  3 6 9 2.000000 1.000000 5.000000 1.000000 8.000000 1.000000