Should `Factory` (function type creating a grpc client) accept a context?

[mqf20]

Should we allow the Factory (function type creating a grpc client) to accept a context so that calls to Factory can timeout or be cancelled?

Proposed changes to pool.go.

Before:

// Factory is a function type creating a grpc client
type Factory func() (*grpc.ClientConn, error)

...

// Get will return the next available client. If capacity
// has not been reached, it will create a new one using the factory. Otherwise,
// it will wait till the next client becomes available or a timeout.
// A timeout of 0 is an indefinite wait
func (p *Pool) Get(ctx context.Context) (*ClientConn, error) {
	...

	var err error
	if wrapper.ClientConn == nil {
		wrapper.ClientConn, err = p.factory()
		if err != nil {
			// If there was an error, we want to put back a placeholder
			// client in the channel
			clients <- ClientConn{
				pool: p,
			}
		}
		// This is a new connection, reset its initiated time
		wrapper.timeInitiated = time.Now()
	}

	return &wrapper, err
}

After:

// Factory is a function type creating a grpc client
type Factory func(context.Context) (*grpc.ClientConn, error)

...

// Get will return the next available client. If capacity
// has not been reached, it will create a new one using the factory. Otherwise,
// it will wait till the next client becomes available or a timeout.
// A timeout of 0 is an indefinite wait
func (p *Pool) Get(ctx context.Context) (*ClientConn, error) {
	...

	var err error
	if wrapper.ClientConn == nil {
		wrapper.ClientConn, err = p.factory(ctx)
		if err != nil {
			// If there was an error, we want to put back a placeholder
			// client in the channel
			clients <- ClientConn{
				pool: p,
			}
		}
		// This is a new connection, reset its initiated time
		wrapper.timeInitiated = time.Now()
	}

	return &wrapper, err
}