node.js's process.stderr.write or process.stdout.write behavier changed by pm2

[tangxinfa]

node.js's define:

bool write(chunk[, encoding][, callback])

see node.js doc

overwrite by pm2 with:

void write(chunk[, encoding][, fd])             // fd is unused.

see pm2 source code

there is no return value to indicate writed data buffered internally, and the callback never called:(

[Unitech]

PR welcome :)