A single client capability flag a server checks before issuing the
corresponding server->client request. Used by ClientCapabilities.supports
and RequestContext.clientSupports so capability gating is type-checked
rather than keyed on a magic string that silently fails on a typo.
A single client capability flag a server checks before issuing the corresponding server->client request. Used by ClientCapabilities.supports and RequestContext.clientSupports so capability gating is type-checked rather than keyed on a magic string that silently fails on a typo.