how to write binary data to csv file in R

I am trying to write binary data to a csv file for further reading this file with 'read.csv2', 'read.table' or 'fread' to get a dataframe. The script is as follows:

library(iotools)
library(data.table)

#make a dataframe 
n<-data.frame(x=1:100000,y=rnorm(1:100000),z=rnorm(1:100000),w=c("1dfsfsfsf"))

#file name variable 
file_output<-"test.csv"

#check the existence of the file -> if true -> to remove it
if (file.exists(file_output)) file.remove(file_output)
#create a file
file(file_output, ifelse(FALSE, "ab", "wb"))

#to make a file object
zz <- file(file_output, "wb")
#to make a binary vector with column names
rnames<-as.output(rbind(colnames(n),""),sep=";",nsep="\t")
#to make a binary vector with dataframe
r = as.output(n, sep = ";",nsep="\t")

#write column names to the file
writeBin(rnames, zz)
#write data to the file
writeBin(r, zz)
#close file object
close(zz)

#test readings
check<-read.table(file_output,header = TRUE,sep=";",dec=".",stringsAsFactors = FALSE
                  ,blank.lines.skip=T)
str(check)
class(check)

check<-fread(file_output,dec=".",data.table = FALSE,stringsAsFactors = FALSE)
str(check)
class(check)

check<-read.csv2(file_output,dec=".")
str(check)
class(check)

The output from the file is attached:

My questions are:

1. how to remove the blank line from the file without downloading to R?
   It has been made on purpose to paste a binary vector of colnames as a dataframe. Otherwise colnames were written as one-column vector. Maybe it is possible to remove a blank line before 'writeBin()'?

2. How make the file to be written all numeric values as numeric but not as a character?

I use the binary data transfer on purpose because it is much faster then 'write.csv2'. For instance, if you apply

system.time(write.table.raw(n,"test.csv",sep=";",col.names=TRUE))

the time elapsed will be ~4 times as less as 'write.table' used.