Go goroutine

Ex 9.1 Add a function Withdraw(amount int) bool to the gopl.io/ch9/bank1 program. The result should indicate whether the transaction succeeded or failed due to insufficient funds. The message sent to the monitor goroutine must contain both the amount to withdraw and a new channel over which the monitor goroutine can send the boolean result back to Withdraw.

Ex 8.6 Add depth-limiting to the concurrent crawler. That is, if the user sets -depth=3, then only URLs reachable by at most three links will be fetched.

Ex 8.1 Modify clock2 to accept a port number, and write a program, clockwall, that acts as a client of several clock servers at once, reading the times from each one and displaying the results in a table, akin to the wall of clocks seen in some business offices. If you have access to geographically distributed computers, run instances remotely ; otherwise run local instances on different ports with fake time zones.