Poor performance of read.metadata compared to showinf from bftools

[aoles]

Calls to read.metadata take significantly longer than readout using the command line tool showinf from bftools. For example, for the sample file from #11 it's 6x slower.

library(RBioFormats)
library(magrittr)
library(microbenchmark)

f <- "Data1051.cxd"

microbenchmark(times = 10,
  a = read.metadata(f),
  b = system(paste0("bftools/showinf -nopix ", f), intern = TRUE)
)

## Unit: seconds
##  expr       min        lq      mean    median        uq       max neval
##     a 11.337970 11.822990 12.102046 12.004656 12.198552 13.531961    10
##     b  1.773676  1.836837  1.894419  1.859554  1.896917  2.275523    10