Apple hasn’t created a module map for that system header, which means
it can’t be used from frameworks.

Cocoapods 1.0 keeps the directory structure of the public headers when
creating a dynamic framework, so if we keep the header_mappings_dir as it
was, includes would need to be of the form #include <openssl/openssl/ssl.h>

This means our header_mappings_dir has to be ‘include/openssl’ instead of
‘include’. Which in turn means that, for static libraries, we have to tell
Cocoapods to prepend an ‘openssl’ directory to the headers. We do that
with the ‘header_dir’ attribute of the podspec.

GRPCHost now has a property channelCreds which is used when creating a GRPCChannel.

For GRPCOperation's, ensure finish _handler can only be called once, and release it when called, so weak ptrs needn't be used with it, and the call won't be released until the finish handler is called.
When the connectivityMonitor determines the connection has been lost, pull the host disconnect call. Creates an unreliable connection when connectivity is restored. Calling finishWithError: is sufficient.

Revert "Redo "Pass a non-infinite deadline to grpc_completion_queue_next() to prevent queues from blocking indefinitely in poll()""

Revert "Revert "Pass a non-infinite deadline to grpc_completion_queue_next() to prevent queues from blocking indefinitely in poll()""

Move C-layer call creation into GRPCChannel, so that it always acts on a
non-destroyed channel.

Listen for connectivity in the GRPCCall, and destroy the channel.

Revert "Pass a non-infinite deadline to grpc_completion_queue_next() to prevent queues from blocking indefinitely in poll()"

Update Podfile for CocoaPods 1.0 changes requiring more fields and the removal of link_with in podspec.

Pass a non-infinite deadline to grpc_completion_queue_next() to prevent queues from blocking indefinitely in poll().