-

         $ strace -f -e read bash -c '( printf 12345; sleep 2 ) | ( read -t 1 -N 10 v; echo "<$v>" )'
         read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0n\1\0\0\0\0\0"..., 832) = 832
         read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\200\r\0\0\0\0\0\0"..., 832) = 832
         read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\3\2\0\0\0\0\0"..., 832) = 832
         read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0pu\1\0\0\0\0\0"..., 832) = 832
         read(3, "# GNU libc iconv configuration.\n"..., 4096) = 4096
         read(3, "1002//\tJUS_I.B1.002//\nmodule\tJUS"..., 4096) = 4096
         read(3, "ISO-IR-110//\t\tISO-8859-4//\nalias"..., 4096) = 4096
         read(3, "\t\tISO-8859-14//\nalias\tISO_8859-1"..., 4096) = 4096
         read(3, "IC-ES//\nalias\tEBCDICES//\t\tEBCDIC"..., 4096) = 4096
         read(3, "DIC-CP-ES//\t\tIBM284//\nalias\tCSIB"..., 4096) = 4096
         read(3, "//\nalias\tCSIBM864//\t\tIBM864//\nal"..., 4096) = 4096
         read(3, "BM939//\nmodule\tIBM939//\t\tINTERNA"..., 4096) = 4096
         read(3, "EUC-CN//\nalias\tCN-GB//\t\t\tEUC-CN/"..., 4096) = 4096
         read(3, "T//\nmodule\tISO-2022-CN-EXT//\tINT"..., 4096) = 4096
         read(3, "//\t\tISO_5428//\nalias\tISO_5428:19"..., 4096) = 4096
         read(3, "CII-8\t1\n\n#\tfrom\t\t\tto\t\t\tmodule\t\tc"..., 4096) = 4096
         read(3, "\tfrom\t\t\tto\t\t\tmodule\t\tcost\nalias\t"..., 4096) = 4096
         read(3, "712//\t\tINTERNAL\t\tIBM12712\t\t1\nmod"..., 4096) = 2847
         read(3, "", 4096)                       = 0
         strace: Process 9860 attached
         strace: Process 9861 attached
=====>   [pid  9861] read(0, "12345", 10)        = 5
         [pid  9861] read(0, strace: Process 9862 attached
          <unfinished ...>
         [pid  9862] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\3\2\0\0\0\0\0"..., 832) = 832
         [pid  9861] <... read resumed> 0x6d2340, 5) = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
         [pid  9861] --- SIGALRM {si_signo=SIGALRM, si_code=SI_KERNEL} ---
=====>   <>
         [pid  9861] +++ exited with 0 +++
         [pid  9862] +++ exited with 0 +++
         [pid  9860] --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=9862, si_uid=996, si_status=0, si_utime=0, si_stime=0} ---
         [pid  9860] +++ exited with 0 +++
         --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=9861, si_uid=996, si_status=0, si_utime=0, si_stime=0} ---
         +++ exited with 0 +++