handling errors with tls

# Tcl: 8.6.4
# http: 2.8.9
# tls: 1.6.7 (OpenSSL 1.0.2d 9 Jul 2015)
# Fetching https://google.com/ ...
# OK! 261 bytes
# Fetching https://1337x.to/ ...
# ERROR: error flushing "sock24ad900": connection reset by peer
# Fetching https://google.com/ ...
# OK! 261 bytes

puts "Tcl: [package require Tcl]"
puts "http: [package require http]"
puts "tls: [package require tls] ([tls::version])"
http::register https 443 tls::socket

# if this is omitted, the message appears on stderr during the next request *after* 1337x.to:
#   SSL channel "sock1829830": error: tlsv1 alert internal error
::tls::init -command ::tls_cb

proc tls_cb {what args} {
    #puts "TLS: $what $args"
    return 1    ;# cert OK, for "verify"
}

# wrapper with error handling
proc fetch {url} {
    puts "Fetching $url ..."
    try {
        set t [::http::geturl $url]
        set d [::http::data $t]
        ::http::cleanup $t
        puts "OK! [string length $d] bytes"
    } on error {e o} {
        puts "ERROR: $e"
    }
}

fetch https://google.com/   ;# this succeeds
fetch https://1337x.to/     ;# this fails
fetch https://google.com/   ;# then a (harmless?) error is emitted here