Thank you for reporting this. Although it's 0.6.0, the same logic exists in the current master.

The problem is basically WaitGroup does not allow Wait() and Add() to run concurrently. (Add() itself can run concurrently). This is clearly explained in the Go WaitGroup source code at https://github.com/golang/go/blob/master/src/sync/waitgroup.go#L30

// Add adds delta, which may be negative, to the WaitGroup counter.
// If the counter becomes zero, all goroutines blocked on Wait are released.
// If the counter goes negative, Add panics.
//
// Note that calls with a positive delta that occur when the counter is zero
// must happen before a Wait. Calls with a negative delta, or calls with a
// positive delta that start when the counter is greater than zero, may happen
// at any time.
// Typically this means the calls to Add should execute before the statement
// creating the goroutine or other event to be waited for.

The WaitGroup, incomingRequestsWG, in the connection.go waits all the sent requests before close the main run goroutine. The design is for run() wait for any requests to be completed if there is any. So both Wait() and Add() are in this concurrent manner. The code should preemptively Add(1) before Wait() is called in the closeCh triggered.

Thank you for reporting this. Although it's 0.6.0, the same logic exists in the current master.

The problem is basically WaitGroup does not allow Wait() and Add() to run concurrently. (Add() itself can run concurrently). This is clearly explained in the Go WaitGroup source code at https://github.com/golang/go/blob/master/src/sync/waitgroup.go#L30

// Add adds delta, which may be negative, to the WaitGroup counter.
// If the counter becomes zero, all goroutines blocked on Wait are released.
// If the counter goes negative, Add panics.
//
// Note that calls with a positive delta that occur when the counter is zero
// must happen before a Wait. Calls with a negative delta, or calls with a
// positive delta that start when the counter is greater than zero, may happen
// at any time.
// Typically this means the calls to Add should execute before the statement
// creating the goroutine or other event to be waited for.

The WaitGroup, incomingRequestsWG, in the connection.go waits all the sent requests before close the main run goroutine. The design is for run() wait for any requests to be completed if there is any. So both Wait() and Add() are in this concurrent manner. The code should preemptively Add(1) before Wait() is called in the closeCh triggered.

What time can this pr be merged？