End of Life Ruby 3.0 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

Net::POP3#set_debug_output

set_debug_output(arg)

# File tmp/rubies/ruby-3.0.5/lib/net/pop.rb, line 485
def set_debug_output(arg)
  @debug_output = arg
end

WARNING: This method causes a serious security hole. Use this method only for debugging.

Set an output stream for debugging.

pop = Net::POP.new(addr, port)
pop.set_debug_output $stderr
pop.start(account, passwd) do |pop|
  ....
end

See also #reset #start #read_timeout= #started?